Gitlab's UI changes every now and then, for seemingly no reason. The UI is very full of stuff (hard to find your way around), and very slow. Notably in the past months, they've changed the issues/tickets board into a "work items" board which feels infinitely slower to load, has such a vague meaning that nobody can find it (especially when translated), and brings exactly 0 use to anyone i know. They just seem to be doing that with every feature and every part of the interface.
On the server side, gitlab was always very hard to selfhost with many moving parts, many requirements, and using much resources. gitlab-runner is not very explicit about things when you're not in the happy path (why is it not picking up jobs?).
I'm not even a minimalist. I've been running gitea/forgejo for the past 8 years or so and it's been a miracle in comparison: lightweight server, easy setup/upgrades, and super simpler UI/UX that everybody understands on the first try. Forgejo (gitea community fork) learns from everything that Github historically made good (UX) without any enshitiffication in sight (developed by a non-profit). I highly recommend it.