Very happy to see this. An old side project of mine randomly became a very popular bot on discord and when discord.py shut down I decided to just let my bot die whenever the API no longer supported discord.py. I likely still will let it die if the developer experience using discord continues to be hell especially when compared to telegram. I think that bots add a lot to a platform and I'll be sad to sunset a project that is being enjoyed by so many but I have no desire to support a platform that doesn't respect developers.
As a person whom has built telegram, slack and teams bots.
Telegram is definitely not the worst, in fact, it's the best on that list depending on what you want to do.
Slack's real-time API has been deprecated since forever, leaving you only specific slash commands that hit web hooks, which does not allow for rich engagement of content or anything close to being as dynamic as the old IRC bots used to be.
