Make sure you’re not using extensions that can server as adblockers
Might need to clear cookies/cache.
It’s a constant back and forth between YouTube and all adblockers. In general, places like Brave, uBlock, and others are all working together to maintain the most recent scripts. Yet at the same time, YouTube/Google/Alphabet is doing their best to prevent adblockers and get people to view ads or pay for premium services. As such, they are also constantly changing code to try to prevent.
All that means is every once in a while YouTube’s changes will slip through content filters. If updating and clearing like that doesn’t work, then it just means we might have to wait up to about 6-24 hours before next filters are modified and released. It’s a headache.