YouTube is already a sedated, anaemic whale of a website. Adblock probably makes it run faster, given it usually removes stuff rather than add it. If you want speed, I recommend a frontend such as Invidious or Piped, it’s what I use on my weaker laptops where YouTube takes half a minute to load.
Sounds like Firefox text mode with extra steps. Granted, it might be good for other browsers, but I personally am doing fine so far with a reader plugin on Palemoon.
Also, as other users have mentioned already, it’s sus as heck.
After trying both, I’ve settled on Invidious. I prefer the UI, it feels more snappy than Piped. Plus, with Piped I had this problem with longer videos where it’d just stop playing somewhere in the middle. Might be fixed by now though.