Use your best judgment and always research the provider.
Using a specific app isn’t always a sign someone is a scam.
I use WhatsApp to communicate with clients as it’s easier to arrange video calls if they don’t have an iPhone/facetime.
But I also have a solid reputation and lots of ways to verify who I am.
I believe telegram is used often by Asian providers and agencies. But also providers from other countries. Using an app doesn’t mean you’re going to get scammed, just make sure you can verify the person on the other end before making any arrangements with them.