I hope you can resolve the issue, I'm sure there can be made some allowances for build and upload problems!
Nah, it's alright. It was all for fun, anyway, and I didn't really get to where I wanted. Weird issue, though!
I had a crashing error too and I don't know why but it seems it came from the unity terrain, cause when I deleted it, it worked.
Wow, I literally just figured this out, too, after hours of playing around trying to narrow down the problem. Yep, it's the terrain. If you're also using the URP-PSX shader, it's putting the shader on the terrain that causes the crash. Exporting seems to work now with normal textures, but I think building the terrain from scratch is probably the better option.