Manifest V3 as specified by google isn't a slight limitation. You must ship your much smaller block list with your extension and only update it with extension updates and due to effectively being limited to only providing a slightly different list of sites to block instead of methodology of blocking your ability to block an evolving threat will be limited to how fast google an ad company opts to evolve their technology to block their own revenue stream.

It only wont immediately appear as the total destruction of adblocking because it will require months for people to all adopt new browser versions and developers are likely to take months to adapt their tech to the point where your adblocker effectively stops working for 90% of ads after which it will basically never work again.