Don't do that! The algorithm counts that as an engagement action.
What you need to do is click on the three dots symbol next to the video title and select "don't recommend this channel". This absolutely fixes it. You may have to do this a lot. There is also a general "don't recommend this" option that, anecdotally, doesn't work as well.
Also, disable autoplay. It doesn't seem like YT can distinguish between clicking on a video and it just playing on autoqueue.
The YT algorithm is not fundamentally different from the other social media algorithms out there: it tries to serve you up with controversial content that "engages" you. You are most likely to be "engaged" by content you either directly disagree with, or by second-source channels that report on content you disagree with. As a fallback, the algorithm will also try to serve you content based on your cohorts, which can in of itself be pretty radical and disagreeable.
Get a YT Premium account if you can, sending a very small message that you vote against ads and all the algorithmic baggage that comes with them.