This code is a total disaster ... preserved here as a cautionary example - hope to be able to create a way better solution soon.

100DaysOfSwitfUI - Day 25.swift

//
//  ContentView.swift
//  RockPaperScissors
//
//  Created by nmbr73 on 17.09.22.
//

import SwiftUI



struct Game {

    static let kindergarden = "Kindergarden"
    static let sheldon = "Go full Sheldon"
    
    static let rock = 0
    static let paper = 1
    static let scissors = 2
    static let lizard = 3
    static let spock = 4

    static let modes = [kindergarden, sheldon]

    
    static func random(mode: String) -> Int {
        Int.random(in: rock...(mode == kindergarden ? scissors : spock))
    }
    
    struct Element {
        let emoji: String
        let name: String
        let isSuperiorTo: [(String,Int)]
        let isDefeatedBy: [(Int,String)]
    }

    
    
    static var elements = [
        Element(emoji: "👊👊🏻👊🏼👊🏽👊🏾👊🏿🪨", name: "Rock", isSuperiorTo: [("blunts",scissors),("crushes",lizard)], isDefeatedBy: [(paper,"wraps"),(spock,"vaporizes")] ),
        Element(emoji: "✋✋🏻✋🏼✋🏽✋🏾✋🏿🧻", name: "Paper", isSuperiorTo: [("wraps",rock),("disproves",spock)], isDefeatedBy: [(scissors,"cuts"),(lizard,"eats")] ),
        Element(emoji: "✌️✌🏻✌🏼✌🏽✌🏾✌🏿✂️", name: "Scissors", isSuperiorTo: [("cuts",paper),("decapitates",lizard)], isDefeatedBy: [(rock,"blunts"),(spock,"smashes")] ),
        Element(emoji: "🤏🤏🏻🤏🏼🤏🏽🤏🏾🤏🏿🦎", name: "Lizard", isSuperiorTo: [("eats", paper),("poisons", spock)], isDefeatedBy: [(rock,"crushes"),(scissors,"decapitates")] ),
        Element(emoji: "🖖🖖🏻🖖🏼🖖🏽🖖🏾🖖🏿🧝", name: "Spock", isSuperiorTo: [("smashes", scissors),("vaporizes", rock)], isDefeatedBy: [(paper,"disproves"),(lizard,"poisons")] ),
    ]

    static func emojiSet(_ element: Int) -> String {
        return elements[element].emoji
    }

}



// https://www.hackingwithswift.com/example-code/strings/how-to-read-a-single-character-from-a-string

extension String {
    subscript(i: Int) -> String {
        return String(self[index(startIndex, offsetBy: i)])
    }
}


struct Emoji: View {
    
    private let rainbow: Int
    private let asterisk: Int
    private let emojiSet: String
    private let theme: String

    
    static func randomRainbow() -> Int {
        Int.random(in:0...5)
    }
    
    
    static func randomAsterisk() -> Int {
        Int.random(in:0...6)
    }
    
    static let themes = ["👶","👶🏻","👶🏼","👶🏽","👶🏾","👶🏿","🌈","🧸","✳️"]

    func string() -> String {
        
        let charPos: Int
        
        switch theme {
        case "👶": charPos = 0
        case "👶🏻": charPos = 1
        case "👶🏼": charPos = 2
        case "👶🏽": charPos = 3
        case "👶🏾": charPos = 4
        case "👶🏿": charPos = 5
        case "🌈": charPos = rainbow
        case "🧸": charPos = 6
        case "✳️": charPos = asterisk
        default: charPos = asterisk
        }
        
        return emojiSet[charPos]
    }
    
    init(for element: Int, theme: String, rainbow: Int, asterisk: Int) {
        //self.element=element
        emojiSet = Game.emojiSet(element)
        self.theme = theme
        self.rainbow = rainbow
        self.asterisk = asterisk
    }
    
    
    var body: some View {
        Text(string())
    }
    
}

let initialEmojiTheme = "✳️"
let initialGameMode = Game.sheldon

struct ContentView: View {
    
    
    // ----- Emoji Theme

    @State private var emojiTheme = initialEmojiTheme
    
    var emojiThemePicker: some View {
        Picker("Emoji Theme", selection: $emojiTheme) {
            ForEach(Emoji.themes, id: \.self) {
                Text($0)
            }
        }
        .pickerStyle(.segmented)
    }
    
    
    
    // ----- Game Mode

    @State private var gameMode = initialGameMode
    
    var gameModePicker: some View {
        Picker("Game Mode", selection: $gameMode) {
            ForEach(Game.modes, id: \.self) {
                Text($0)
            }
        }
        .pickerStyle(.segmented)
    }

    
    


    @State private var computersChoice = Game.random(mode: initialGameMode)
    @State private var computersChoiceRainbow =  Emoji.randomRainbow()
    @State private var computersChoiceAsterisk = Emoji.randomAsterisk()
    
    
    @State private var humandWins2ndOption = Int.random(in: 0...1)
    @State private var humanWinsRainbow =  Game.random(mode: initialGameMode)
    @State private var humanWinsAsterisk = Emoji.randomAsterisk()

    @State private var humandLooses2ndOption = Int.random(in: 0...1)
    @State private var humanLoosesRainbow =  Game.random(mode: initialGameMode)
    @State private var humanLoosesAsterisk = Emoji.randomAsterisk()


    @State private var computerShouldWin = Bool.random()
    @State private var humanWinsOnLeft = Bool.random()
    
    @State private var score = 0

    
    var humanShouldWin: Bool { !computerShouldWin }
    var humanShouldLoose: Bool { computerShouldWin }


    @State private var lastAnswerReason = ""
    @State private var lastAnswerCorrect = false

    @State private var endGame = false
    let rounds = 5

    @State private var round = 1
    
    func shuffle() {
        computersChoice = Game.random(mode: gameMode)
        
        computersChoiceRainbow = Emoji.randomRainbow()
        computersChoiceAsterisk = Emoji.randomAsterisk()

        humandWins2ndOption = Int.random(in: 0...1)
        humanWinsRainbow = Emoji.randomRainbow()
        humanWinsAsterisk = Emoji.randomAsterisk()

        humandLooses2ndOption = Int.random(in: 0...1)
        humanLoosesRainbow = Emoji.randomRainbow()
        humanLoosesAsterisk = Emoji.randomAsterisk()
        
        computerShouldWin.toggle()
        humanWinsOnLeft = Bool.random()
        
        
        if round == rounds {
            endGame = true
        }

        round += 1
    }
    
    func restart() {
        lastAnswerReason = ""
        score = 0
        round = 0
        shuffle()
    }
    

    
    var body: some View {
        
        VStack {


            Spacer()

            Text("My choice:")

            Emoji(for: computersChoice, theme: emojiTheme, rainbow: computersChoiceRainbow, asterisk: computersChoiceAsterisk)
                .font(.system(size:120))

            
            Text("Choose wisely to \( computerShouldWin ? "let me win" : "make me loose" ):")

            HStack {

                let humanWins = Game.elements[computersChoice].isDefeatedBy[ gameMode == Game.kindergarden ? 0 :  humandLooses2ndOption ].0
                
                let humanWinsButton = Button {
                    lastAnswerReason =  Game.elements[humanWins].name + " " + Game.elements[computersChoice].isDefeatedBy[ gameMode == Game.kindergarden ? 0 :  humandLooses2ndOption ].1 + " " + Game.elements[computersChoice].name

                    lastAnswerCorrect = false

                    if humanShouldWin {
                        score += 1
                        lastAnswerCorrect = true
                    }

                    shuffle()
                    
                } label: {
                    Emoji(for: humanWins, theme: emojiTheme, rainbow: humanWinsRainbow, asterisk: humanWinsAsterisk)
                        .font(.system(size:120))
                }


                let humanLooses = Game.elements[computersChoice].isSuperiorTo[ gameMode == Game.kindergarden ? 0 :  humandLooses2ndOption ].1
                
                let humanLoosesButton = Button {
                    lastAnswerReason =  Game.elements[computersChoice].name + " " + Game.elements[computersChoice].isSuperiorTo[ gameMode == Game.kindergarden ? 0 :  humandLooses2ndOption ].0 + " " + Game.elements[humanLooses].name

                    lastAnswerCorrect = false
                    
                    if humanShouldLoose {
                        score += 1
                        lastAnswerCorrect = true
                    }

                    shuffle()
                                                            
                } label: {
                    Emoji(for: humanLooses, theme: emojiTheme, rainbow: humanLoosesRainbow, asterisk: humanLoosesAsterisk)
                        .font(.system(size:120))
                }

                if humanWinsOnLeft {
                    humanWinsButton
                    humanLoosesButton
                } else {
                    humanLoosesButton
                    humanWinsButton
                }
                
            }


            Spacer()

            Text(lastAnswerReason)
                .foregroundColor(lastAnswerCorrect ? .green : .red )

            Text("Your Score: \(score)" + (round <= rounds ? " (round \(round) / \(rounds))" : ""))
 
            
            emojiThemePicker
            gameModePicker
            

        } // VStack
        .alert("That's it", isPresented: $endGame) {
                    Button("OK") {
                        restart()
                    }
                } message: {
                    Text("You scored \(score) out of \(rounds)")
                }
    } // body
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}