I'll say it a million times: they tried to copy several games but ignored the development structure that made them successful: release a minimum version and work on it alongside the community.
A lot of people saw this coming since when they announced that they were completely restarting development of their engine.
They let perfect be the enemy of good enough and so not a single build ever saw public release.
It's an engine that puts everyone else before programmers - which is great for artists and designers as they can blueprint animations and simple things. It's bad however when the performance relies on programmers whose time is already torn between trying to do things The Unreal Way™️ and fixing bugs caused by someone doing more than they should have in one big and messy blueprint hotpot.