Thanks for updating the post.
I keep trying to understand the situation. I use Opera on two different machines, with coordinated settings.
Both machines are Apple Macs.
One machine has OS 11.7 and the YT blocking on this one is 100%, I cannot play a single YT video.
The other machine runs OS 14.0 and on this one the ads are not skipped, but run as 'dark blanks', for the duration of the add, a black screen appears with just the first and last frame of the ad being shown, without sound.