as far as I know, yahoo62278 and Hhampuz have the most experience with "other" campaign types. Testing, sign-ups or other tasks, not just signatures or social media reposts.
I am not sure that telegram-based exchange would be a good idea, and I can see several potential exploits and abuse, but I would have to see how it works in real life first before judging.
in our local language
Serbian topic, one member started/promoted something similar. Telegram bot for exchange without a fee. but only for local members, because fiat payout is done through ATM. as far as I could see, now all trades are made by direct agreements.