The lack of support is in the other direction - Safari doesn't support uBlock Origin anymore. The only way to block ads is with Apple's Content Blocking API, which is fundamentally not how uBlock Origin works.
Originally, Google wanted to max at 30k items, but after the outry, they increased it to 150k.
For comparison, my uBlock has currently 101k of net filters and 49k cosmetic filters.
Edit: I see it’s ublock, not ublock origin. What’s the difference?
If it's in the App Store, it's not even a fork, it's just some piece of software using the "uBlock" name.