i know of one person that upgraded to Windows 11, and he got it up and running just fine and is working in MendixStudio Pro versions 8.17.0, 8.18.15 and 9.6.6. So that kind of says that Windows11 is ok for running Studio Pro. Not very helpful though.
Have you tried to first log in to sprintr.home.mendix.com?
I logged in to mendix website and clicked edit in mendix pro, my project. Somehow, the log in page was loaded but was unresponsive. I typed invisible letters on user and password fields. And clicked unclickable sign in. Got logged in!
I logged in to mendix website and clicked edit in mendix pro, my project. Somehow, the log in page was loaded but was unresponsive. I typed invisible letters on user and password fields. And clicked unclickable sign in. Got logged in!