This tool will mark all of your Discord Servers as read, getting rid of that pesky NEW thing. Requires Python 3.7+ and a Discord Token.

ack.py

import requests
import time
import sys, argparse

app_name = "DiscordAckkyBoi"; version = "2.0"; username = "heckboi"
base = "https://discordapp.com/api/v6"

print(f"[{app_name}/{version}] Hello World!")

class Discord:

    def __init__(self, token):
        self.token = token
        self.headers = {"authorization": token}

    def check_token(self):
        """ 
        Check the token is valid, also greet the user, cause i'm a good boy"""

        request = requests.get(f"{base}/users/@me", headers=self.headers)
        if request.status_code == 200:
            username = request.json()["username"]
            print(f"[{app_name}/{version}] Welcome to {app_name}, {username}!")
            return True
        elif request.status_code == 401:
            print(f"[{app_name}/{version}] Invalid token!")
        else:
            print(request.text)
            return False

    def get_guilds(self):
        """ 
        Get a list of guilds the user is in"""

        request = requests.get(f"{base}/users/@me/guilds", headers=self.headers)
        
        if request.status_code == 200:
            return request.json()
        else:
            print(request.text)
            return False

    def ack_guild(self, guild):        
        request = requests.post(f"{base}/guilds/{guild}/ack", headers=self.headers)
        if request.status_code == 204: # Success
            print(f"       -> Ack {guild} OK.")
        else:
            print(f"       -> Ack {guild} Failed. ({request.text})")



if __name__ == "__main__":
    # Check for arguments
    
    parser = argparse.ArgumentParser(description=app_name)
    parser.add_argument("-t", type=str)
    
    args = parser.parse_args()  

    token = None

    if args.t == None:
        print(f"[{app_name}/{version}] Parse Error: Please provide a token with the -t <token> argument.")    
        sys.exit(2)
    else:
        token = args.t

    discord = Discord(token)

    if discord.check_token():
        # Get list of guilds
        print(f"[{app_name}/{version}] Getting guilds...")
        guilds = discord.get_guilds()
        if guilds != False:
            print(f"[{app_name}/{version}] Get guilds success, you're in {len(guilds)} guilds!")
            print(f"[{app_name}/{version}] This will take {len(guilds)} seconds to complete (1/second)")

            for guild in guilds:
                # BAD BAD BAD CODE NEV.
                # I'm sorry
                name=guild["name"]; guild_id = guild["id"]
                print(f"[{app_name}/{version}] Ack'ing {name} ({guild_id})...")
                discord.ack_guild(guild_id)
                time.sleep(1)
            
            print(f"[{app_name}/{version}] All done... for now.")
        else:
            print(f"[{app_name}/{version}] Sorry {username}, I failed to get guilds... I'm a bad boy.")
            exit()
else:
    print("[FAIL] Don't import me! Run me standalone!")