Weird, I watch YT quite a bit but it only suggests things that are related to stuff I've watched before, and I don't recall ever seeing a political video on there show up.
That's totally weird because I have never watched a political video on YouTube, yet my whole suggested feed is filled with it. Even in the first 3 suggested videos. All of it is very far right conservative. Never touch it. I login to see if anyone I'm interested in has posted anything new then get off the platform. Have no clue how to get out of it.
I find the opposite; YouTube is on a constant mission to pull me into the world of right-wing videos with angry titles and antivax propaganda.
If you browse YouTube with cookies disabled or within a cookie fence, you can see that such manipulation is the default behavior. For a significant percentage of videos, the very first set of suggestions is manipulative. For the others, perhaps the first set of suggestions is not problematic but the suggestions for those videos are where the manipulation starts.
It's nice that you found a way out of it but I'm guessing that's rare.
That being said, I live in the UK.
We know it's going to base its default recommendations based on your perceived location.
I personally found that I needed to make an account to get away from the horrendous default recommendations. And allow it to use some data and not clear my cookies etc.
You're mostly correct, but I'm guessing you don't use the feature of marking videos as not interesting - it really helps, to the degree that I don't get suggested almost any right-wing videos of the disgusting kind even when I listen to music popular in those circles, as evidenced in the comments sections (I prevailingly use YT for music). Now, if only there was an option to filter out the nationalistic comments (insubstantial comments calling for "unity among brethren" and similar), too.
One has to log in to benefit from this, though.
However, most YT advertisements that get served to me are scams the last few months.