Check out
https://gitlab.kitware.com/users/sign_in
or
https://gitlab.xiph.org/users/sign_in
You can sign up with your GitHub account.
https://gitlab.gnome.org/users/sign_in even allows you to login with a GitLab account. Which ironically isn't possible on these other two.
If a project has self hosted infra and wants me to sign up to their Bugzilla I think twice before doing so.
And if github really turns to shit because Microsoft shows their true evil face you can just move platforms again.