Gitea is OK,but there is no one big instance(yes,I know about codeberg) . Sourcehut is made by one-man in his one-man shop,and it lacks many features that one needs.Also,it is Alpha software.
Bloated how? There is a lot of functionality in gitlab, and maybe there is a fair argument that the product itself is bloated, but the UI seems pretty appropriate for the functionality. Maybe I'm just used to it though.
But,UI wise , Github is very much slim ,fast and quick. It will function without js. Gitlab although functional will take very much time to load a page(because ,js is used a lot).Making it PWA would solve the problem but it is still not made PWA.
Currently UI looks more like it's been designed by people who write code rather than those who have spent considerable time thinking through user interactions and designing based on that. So it's not bloated in terms of the code and libraries, but rather all of the functionality is just thrown to the user as is without much thought.