Blender is overextended. That's what Blender developers said openly. Parts like the compositor don't get much love at all. They were merely included because they were needed to fill huge gaping holes in the production pipeline for their demo movies. After that, interest in them dropped to near zero, but there were no better alternatives for a long time.

Now, there is at least Neutron as an open source compositing tool that seems to be filling that particular hole now much more competently than Blender ever could.

I do not understand how you can consider Blender's UI "manageable" in any way. There are much better ways to build UIs for enormously complex DCC tools. My go-to example for that has been Maya for a long time, but since a couple of years, Autodesk has bolted on features in a way that spectacularly breaks the internal consistency, logic and general discoverability of features in Maya. Even though, Blender's UI is still an unsorted mess compared to that.