They've been promising to fix performance and the UI for years now, so I wouldn't hold out much hope. It's a shame, but there are better open source products so it's not like there are no other options for self hosted.
We've also got an entire team dedicated to porting our Git layer to Go with Gitaly[1], which has been a major bottleneck that we've started resolving over the last year or so.
[0]: https://gitlab.com/groups/gitlab-org/-/merge_requests?label_... [1]: https://gitlab.com/gitlab-org/gitaly