Just tried the site.
When there is a waterfall of error messages, look for the top-most. It is the zero patient. All the next errors are cascading post-errors and sometimes they are not indicative at all.
In your case, the very first error message is about one of the shaders that is not compiled. This is one of the hardest errors to track, because it means some bad data leaked into Three.js and forced it to build a wrong shader. It looks like it is some bug related to textures and UV coordinates, but in my experience what it looks like is not always what it is. This error is hard, because it happens in one place, but the cause is in a very different place.
My suggestion:
- first try the latest Three.js (just change the importmaps)
- then remove pieces of the code one by one and check whether the same error persist - at some point the error will disappear and this will indicate what part of the code or what feature of the objects caused it
For your reference, here is the first error message that I see (the cannot-read-properties-of-undefined error message pops-up later on):
