unless Brave and other forks (like Cromite, Vanadium, Ungoogled-Chromium) manage to disable MV3, which I think Google will make it impossible to do so, they are affected by this change.
Switch to Firefox.
https://github.com/brave/adblock-rust
Here is a (somewhat dated) article describing it by the authors:
1/ they have adblocking built-in [0]
2/ they will continue to support Manifest V2 indefinitely, esp. so that uBlock Origin continues to work [1]
That doesn't mean uBlock will continue to exist... If it can't be installed on Chrome it's possible the sole dev will lose motivation (although he has already made a V3 version of the extension).