I don't know why with LLMs we can't just add MV2/blocking web request support to Chromium in a fork.

The argument against was always that it's "too hard to keep a fork in sync". Now it's easier.

That's basically exactly what Brave (the only Chromium browser still supporting uBO) is doing to support uBlock Origin. But it's flimsy and likely has an expiration date.

AFAIK they are using the built-in support which Google still maintains even if they don't expose it.

My point is that when MV3 was announced there was an assumption that maintaining a Chromium fork to continue supporting MV2 would be too much work and too expensive. But now with LLMs that's no longer a safe assumption. The non-Chrome chromium based browsers can fork chromium and add back MV2. No need for any expiration date.

Or you could just use Firefox.