I use old.reddit.com, and had trouble logging in from there today. “Too many redirects”. I also use the Redirect to old.reddit.com extension. When I disabled that, the login link it now takes you to is https://www.reddit.com/login/. That, of course, takes you to www.reddit.com.
The old ‘popup’ login box has been removed. I also noticed that the in sub logins where they used to have username/password entry boxes have been removed.
More reddit enshitification to try and make us use their horrible UI.
If you are logged into reddit, you can just set the account preference to opt out of the redesign. No extension needed.