Brave and a few other derivatives will block these high profile features. But they don't have the resources to maintain many of these exceptions. For example look at Brave's response to manifest v2. They say that they will try to support it for longer but they are careful to promise little. Because they know they don't have the resources to maintain all of the underlying APIs and their own extension store.

Plus this helps entrench Chromium as the only browser engine. Because even the addition of many non-harmful features that other engines don't implement create compatibility issues that results in developers using these new features so sites break. Firefox gets unsupported so people have to switch to Chrome or a derivative.

So yes, a derivative is better than using Google Chrome. But it is a small improvement compared to switching to a different browser engine.