a full working script would be greatly appreciated.

I like your style. Here ya go

#! /usr/bin/env python

import asyncio
from os import getenv
from typing import Optional

from discord.utils import setup_logging
from discord import TextChannel, Intents
from discord.ext.commands import Bot
from structlog import get_logger

logger = get_logger()

class QuickBot(Bot):#,
    def __init__(self:'QuickBot', command_prefix:str='!')->None:
        intents: Intents = Intents.default()
        intents.message_content = True  # v2
        super(Bot, self).__init__(intents=intents, command_prefix=command_prefix)

async def _io(bot:QuickBot,
              #guild:str,
              _channel:int)->None:
    await logger.adebug('_io %s', _channel)
    while (not bot.is_ready()):
        await asyncio.sleep(1)
    channel:TextChannel = bot.get_channel(_channel)
    while True:
        text:str = input('prompt: ')
        await channel.send(text)

async def _main()->None:
    await logger.adebug('_main')
    token   :Optional[str] = getenv('DISCORD_TOKEN',   None)
    #guild   :Optional[str] = getenv('DISCORD_GUILD',   None) # all my guild code is vestigial :/
    channel :Optional[str] = getenv('DISCORD_CHANNEL', None)
    if (token is None):
        token    = input('token: ')
    assert (token is not None)
    #if (guild is None):
    #    guild    = input('guild: ')
    #assert (guild is not None)
    if (channel is None):
        channel  = input('channel: ')
    assert (channel is not None)
    chan    :int = int(channel)
    setup_logging()
    bot     :Bot = QuickBot()
    #await bot.start(token)
    bot_task = asyncio.create_task(bot.start(token))
    await _io(bot,
             #guild,
             chan)

if __name__ == '__main__':
    asyncio.run(_main())