SlowMo in CC 3.7.x

GameHandler.ts

import { _decorator, Component, game } from 'cc';
const { ccclass, property } = _decorator;


function timeScalerDT(useFixedDeltaTime){
    this._useFixedDeltaTime = useFixedDeltaTime;

    if (useFixedDeltaTime) {
        this._startTime = performance.now();
        return this.frameTime / 1000;
    }

    const now = performance.now();
    this._deltaTime = now > this._startTime ? (now - this._startTime) / 1000 : 0;
    if (this._deltaTime > Game.DEBUG_DT_THRESHOLD) {
        this._deltaTime = this.frameTime / 1000;
    }
    this._startTime = now;
    return this._deltaTime * (this.timeScale || 1);
}

@ccclass('GameHandler')
export class GameHandler extends TriggerObserver {
    start() {
    
        //initialization of the timeScalled DT. 
        game.timeScale = 1
        game._calculateDT = timeScalerDT

        //example usage. 
        tween(this.node).call(()=>{ game.timeScale = 0.1 }).delay(0.25).call(()=>{ game.timeScale = 1 }).start()
    }
}