(Initial comment - Note possible workaround below)
Same issue - from a Windows Machine (11). Noticed that incorrect creds instantly error out but the correct creds which fail login on UIFlow but work elsewhere cause the same hang as logging in elsewhere, which to be clear still works, the issue is UIFlow specfic for me.. Have tried with email and username + reset to no avail, seems there is an issue, account is relatively new, a few days - <1 week so maybe there's a sync issue or similar?? .
UPDATE - Login worked on chrome after failing on brave - one difference being my email was all caps in chrome. Tried the same on brave with success - seems silly but perhaps theres a a!=A issue and one may need to sign in with the exact same string as used to sign up, an issue which doesnt seem to exist elsewhere.. Hope that helps!