Which can rapidly exceed in size and count the "non-user-facing" objects.

This objection really needs to die. GC does not instantly mean you can't program games. At most it locks you out of the tip-of-the-tippy-top AAAA games, but if you were trying for that you weren't going to use "someone's GitHub project" anyhow. And most of them probably have meaningful GC in them anyhow.

Pretty much everything in unreal aside from the rendering code and platform interaction layers is written in uobject and actor land - which is garbage collected.

The rendering code also isn’t “just” not garbage collected - it eschews all the normal c++ and is written in a totally different way. It might as well be in a different langauge honestly