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".
Just wait until you get to Transunion's site. It is a dumpster fire of consisting of the worst sign up I've ever seen, "Contact our social team" and "If you haven't logged in for awhile create a new account. I could not believe how awful it was. I had to just call and do it over the phone.
Transunion was not too bad, and they did not require my full SSN, unlike Equifax. But transunion will not easily give me my credit score unlike the two Es.