You’re right, this sneaky bastard usually copy everything from an admin especially the username that typically change a little bit like “o” to “0” and other letter to number changes just to look like he is the real admin.
Admins never DM first, never ask for money, never ask for private keys and so on. Remember this principle and people who know about this as well as are careful enough will not be scammed by impersonators.
The scam method you mentioned is quite common. It's
IDN Homograph Attack.
This scam method can be used for phishing sites too.
Punycode Phishing attacks - how to stay safe - Spoofed URLs and fake websites!