MV3 has greater security, and security enforces privacy.
Currently, the Browser Extensions page says
We only recommend this version of uBlock Origin if you never want to make any changes to your filter lists
But PG’s section on Brave Browsers explicitly recommends not to add any filters to Brave Shields, which is an arguably more secure adblocker than uBlock Origin.
Also, MV3 adblockers may be more effective at adblocking than previously assumed:
Lastly, even if Youtube ads are not able to be blocked by uBO Lite, PG already has recommended frontends, and recommends Brave which is tailored to block those ads.