Google has been blocking adblockers, or atleast trying to for some time now. Notably on Youtube.
I barely feel the impact of this because I use Mastodon, Lemmy, Peertube and other services that don’t have ads.
Unlike your traditional website, these services federate, with each other over this Fediverse thing we all know about.
What’s good about this is if, some severs wants to be greedy against it’s users, users can easily just change servers and not have to worry about losing familiarity with the platforms user interfaces that they grew accustomed to.
Legally the largest Mastodon, Peertube servers and other can’t do anything to smaller servers as the software used for the Fediverse platforms, generally are open source and federated with each other with help from activity pub which is also open source.
I finally had a minute to try it out and unfortunately it does not seem to change anything on my 2020 Mac+Intel (the GPU load skyrockets when I watch videos on YouTube)
GPU load should increase when watching videos, even if hardware acceleration is enabled. In about:config, set media.hardware-video-decoding.force-enabled as true and restart firefox. Additional stuff may be needed for Mac which I don’t know.