SATURDAY AM UPDATE: The last-minute push for The Marvels with an appearance by star Brie Larson on The Tonight Show and at a theater in NYC post-actors strike have not moved weekend grosses any hig…
I use freetube which doesn't have a algorithm so avoids that issue, and let's you block channels from appearing in even searches.
But, if insistent on using YouTube.com turning off watch history gets rid of recommendations and blocktube extension allows for channel blocking.
Never had luck with don't recommend this video to me option even though Id go out of my way to avoid visiting any of the videos posted by certain channels. They'd still after a while post the channel content in recommendations, since I guess they are highly trending.
I've actually done a fair job of it but it did require erasing my entire watch history and being extremely generous with the "don't recommend this content/channel" when it allows me to select that.