There is a lot of chatter in the last days about how Youtube is slow with content blockers. Those performance issues affect only the latest version of both Adblock Plus (3.22) & AdBlock (5.17), and afflict more than just Youtube. uBO is not affected.
Comment from a ublock developer on this:
https://twitter.com/gorhill/status/1746263759495077919
I didn’t realize people still used AdBlock Plus, or that it even still existed.