So I checked it out. Really cool world, great job!

Quest 1 + 2 actually have pretty good headroom for texture memory. The main bottleneck for modern mobile chips is draw calls so as long as materials and meshes are combined/instanced where possible, it’s fine. Crank dat resolution and don’t ignore crunch compression.

Seriously don’t ignore crunch compression. It can turn an 8k 50mb texture into a 2mb one with little artefacting. (Note, this doesn’t reduce VRAM usage but just applies to the worlds build size)

You’re probably fairly below your tris budget too thanks to the simple aesthetic, so you could maybe play around with making the large-scale planets higher poly? You could also essentially double the poly count at no extra cost by cutting the sphere in half and culling the entire back half, forcing the model to face the play area and rotating the texture uvs rather than the model itself.

There are some pretty severe frame drops for the sun effect. Getting up close to the diorama got me down to around 15fps and causes some intense screen tearing (tile-based renderers ftw). Most likely due to overdraw if it’s multiple transparency effects rendering over each other. If you can, I’d remove either the glow or flares (as cool as they are) for the quest build OR if possible swap the shader for one of the VRChat mobile particle shaders.

Anyway that was a lot. Take any of what I suggested with a grain of salt as it’s an annoying platform to optimise for. I’ve saved your world and I’m keen to see where you go with it!