The big WGPU project to improve concurrency wasn't finished then. All the texture loading that's requested from other threads currently goes into a work queue inside Rend3 executed by the refresh thread. Because the application is frantically loading and unloading textures at various resolutions as the camera moves, there's a stutter. There's too much texture content for it all to be in VRAM at high resolution all at once. Vulkan allows concurrent loading of data. WGPU now does. (As of this morning, unless someone finds another blocking bug.) Rend3 next. Then I'll probably have to change something in my code. That's what I mean about problems down in the graphics engine room.

This is the metaverse data overload problem - many creators, little instancing. No art director. No Q/A department. No game polishing. It's quite solveable, though.

Those occasional flashes on screen are the avatar (just a block in this version) moving asynchronously from the camera. That's been fixed.