Good job writing this up! When I picked UPBGE I expected the only big performance concern to be highpoly deformations in rig animations, so I thought it’s a no issue for me as I’m doing a very lowpoly thing. Eventually depsgraph turned out a massive problem and at this point every new dozen of objects added to scene hits FPS in mysterious ways, even when there are no constraints or anything like that on those particular objects. Overall I’m using maybe a two dozens of constraints and one simple geonodes setup in the scene, and being able to use those was one the biggest motivations to use UPBGE at all. Turned out they’re really problematic due to depsgraph. I’m sticking with UPBGE for my current project, but I’m really considering moving on afterwards, the way I sticked to organising everything in separate composable components going to make porting it simple. I actually ported enemy ai state machine from my other Godot project to UPGBE, and now it seems I’m going to port evolved version of it either back to Godot or maybe even Unity 😅