I receive this type of offers on telegram a lot, the solution was blocking messages from unknown numbers in telegram settings, I've given more than five people a chance but it all end up a scam, I knew they are lying the moment they say they can't withdraw their own money.
Telegram is the den of this type of scam. Most times when I receive messages from unknown number seeking for help with their wallet/exchange account or trying to teach me how to earn passively I don't even bother to reply them because I already know that it definitely going to end up as a scam or it's just going to waste the time I should have been spending on other things that would have profited me.
And just as you said disabling unknown numbers from reaching on telegram can help you prevent messages like that but that's only if you don't use your Telegram account for business purposes.