Do not trust anyone from telegram without conversation on the forum. Same should follow for website. And we should more conscious while we send fund to any person or website and/or when we invest on any website.
Some are trustworthy, but risk is risk. We found ourselves at risk every time especially that we're dealing with crypto.
Though with regards to what you say, you can have a business transaction with someone from telegram, but know the risks and play it carefully. and just as what you said, it will be normally in this forum if its not a scam, but it will only be known to be scam, if the scamming already started, just like this one