Bethesda doesn’t really like to support its games after release, so everything is now in the hands of the modding community -- which so far has done just fine on its own.
Initially, there were tons of bugs encountered by players all over Skyrim SE. As a result, the unofficial patch fixes all possible and encountered bugs in hundreds of quests, objects, NPCs, etc.
New updates for the mod arrive on a weekly basis, and if you still find some glitches here and there, you can always report them at the USSEP bugtracker’s website.
If you haven’t found the right mod for yourself, then you can suggest some of your own favorite Skyrim SE mods in the comments below.