If Google leaves a boolean switch in Chromium to keep V2 enabled then I assume most if not all of the third party Chromium-derived browsers will just flip it to true by default. That's easy for them to do, the hard part is if Google strips out V2 altogether and leaves the downstream browsers to patch it back in.
Even when it's stripped out entirely, it will be easy to add back in. The changes (that adblockers care about) are just a few if statements changing the conditions under which synchronous inspection of web requests are allowed. Manifest V3 still allows them. But only in limited circumstances which are unsuitable for ad blocking.
I consider my non-technical friends/family technically dead. They're lost souls you can't help, like Elizabeth Swan looking down at her father's ghost on the boat. We can't help.
Freedom and privacy are luxuries only available to those nerdy enough to use Linux. The rest are prey/prisoners/peasants to the technofeudal overlords.
After the XUL removal debacle a number of years ago, I can't trust Firefox to offer a suitably flexible and capable extension system over the long run.
While some people will claim that those changes were necessary, the impact was still very negative for the extension developers and users who were affected at the time.
The numerous other user-hostile decisions made by Firefox's developers certainly don't help repair the trust that was lost then.
Were the poor decisions made by Mozilla engineers or by Mozilla Corporate Executives? Mozilla has never paid engineers particularly well; in the past engineers joined mostly out of a duty bound to philosophical alignment.