If I didn't care about the open source license I'd simply use github. (Which, unfortunately, may be the only solution that doesn't continue eating more and more of my time.)
Anyhow, this sounds like a death knell for gitlab-ce. My GSoC use case isn't fringe (there are 100s of GSoC orgs), and Gitlab wouldn't have spent money on the ML approach for EE if it weren't generally important.
You can run EE without license, it provides the same features as CE. Maybe that is an option for you: https://docs.gitlab.com/ee/update/package/convert_to_ee.html I've created an MR to help clarify the docs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81751