How you can tell which exchanges and financial partners to avoid:

Just look for the tell-tale "US customers not allowed" sign.
Why?
If not able to register in the US, it means the exchange doesn't have to follow any reasonable rules, such as:
NOT raping customers with 100x leverage
No "Japanese-walled" market maker partners (think Alameda Research to FTX relationship)
No Co-mingled assets (customer's with exchange's)
No illegal unregistered securities

In other words, you look for lingo like this which SEEMS like they're being open and "cool", but in reality this is a thinly vieled invitation to use VPN masking to open up an account no matter WHICH country you live, and that's exactly what happens.