Putting aside the technical aspects, those anti-competitive provisions sound very unconscionable and against public policy to me. There's no way they would try to enforce that in a courtroom without being laughed out of it (or worse, getting their copyrights revoked under the "copyright misuse" doctrine)
In the US maybe but it is worth noting that they are a Japanese company and Japanese copyright law is different from US copyright law (ex: no free use).
Yes. If you are a US citizen and you reside in the US when the perceived infringement occurs, then you will go to court in the US with US law (thanks to the Berne Convention).
However this software (Live2D) is originally targeted at the Japanese audience and only after vtubing became popular overseas did it get proper English support. So a significant bulk of the users of this software are individuals who reside in Japan. And on top of that, quite a large population of vtubers live outside the US in regions with their own copyright law. So to the degree this is enforceable will be decided entirely by where you live.
For US non-expat citizens & residents, this isn't a problem but for the rest of the world there is a lot wider variation in how enforceable these license terms are.
