Brave blocks Microsoft Recall by default

The real question is: can recall be forcibly torn out of your system, not if a specific application tries to "block" it.

Probably no more than explorer.exe (i.e. internet explorer integration) can be torn out of windows.

With windows I wouldn't put it past Microsoft to helpfully 'repair' it after any given update, similar with a lot of the privacy tweakers you can find. Then it becomes a monthly task after patch Tuesday to confirm your system is how you want it.

By not turning it ON.

Recall is off by default, it's no more enabled on a clean install than Hyper-V. I think the idea is actually very good, but obviously the privacy concerns are not great. Microsoft has made a lot of changes from what I've seen to allow you to block it on x, y, z, etc.

But removing the whole OS?

explorer.exe is the graphical shell and file browser...

Recall is opt-in.

Yes, it can be removed via the "Turn Windows features on or off" dialog.

It's off by default but still present on the system. You can remove it entirely via the "Turn Windows features on and off" dialog.