You could keep a github mirror of your work with issues/pull requests/wiki/... disabled, have links to your gitlab/issue tracker and automatically push to githu

You could keep a github mirror of your work with issues/pull requests/wiki/... disabled, have links to your gitlab/issue tracker and automatically push to github whenever you push to gitlab or on a cron. This would give you the discoverability of github with the control of your own instance. That is if you are willing to touch github again.