Personally I'm not going to worry about switching until the old API is deprecated, but it should be very simple to write an adblocker for Manifest v3. You coul

Personally I'm not going to worry about switching until the old API is deprecated, but it should be very simple to write an adblocker for Manifest v3. You could put together an MVP by plugging EasyList into the new APIs in probably ten minutes. Obviously a fully-featured blocker requires a lot more time than that though. I'd actually expect a small performance increase because the browser is preloading the block list, rather than querying it every time. uBlock does provide some other feature like disabling network pre-fetching, and I'm not sure if those can be fully replicated. But I tend to prefer the performance improvement of pre-fetching anyway.