Not only does the credit bureau max out their password length, you have a small list of available non-alphanumeric characters you can use, and no spaces. Also you cannot used a plused email address, and it had an issue with my self hosted email alias, forcing me to use my gmail address.
Both Experian and transunion had no password length limitations, nor did they require my username be my email address.
Update: I have been unable to log into my account for the last 3 days now. Every time I try I get a page saying to call customer service. After a total of 2 hours on hold I finally found the issue, you cannot connect to Equifax using a VPN. In addition there is no option for 2FA (not even email or sms) and they will hang up on you if you push the issue of their security being lax. Their reasoning for lax security and no vpn usage is “well all of our other customers are okay with this”.
Username and display name can be set independently, you should have a “Display name” field in settings. Their non-unique display name is “max” and their unique username is “@[email protected]”. If you check their profile you should see both.
If you don’t set a display name it will be the same as your username, if you set display name to the same as username (like I have) it’ll show your username without the instance even to people on other instances.