I don't think this is how YouTube's recommendation algorithm has worked in a long time. I won't argue that the current recommendation algorithm is somehow nefarious in nature, but I'm willing to bet there are factors that are weighed a lot heavier than the fact "I watched A so I should watch B". Your recommendations hardly change based on what video you are watching at the current moment.

My personal theory is that YouTube overemphasizes watch time to a point where any long video gets suggested as long as it has a high completion time. You could be "batshit liberal" and still be stuck in the "alt-right recommendation loop" simply because YouTube thinks you will finish those videos regardless of your political orientation.