fwiw I (a YouTube premium subscriber) recently enabled restricted mode myself due to the app showing me completely unrelated and 'scary' videos in searches.

After some searching I found a few threads where others had encountered this and restricted mode was the only thing that seemed to stop these videos and honestly they're jarring and unwanted enough for me to warrant enabling restricted mode and all the features it disables - YouTube please please stop these unrelated 'jump scare' videos!

as an example I'm scrolling through videos on how to fix a leaky tap at 10pm I'll come across a thumbnail 5 videos down with a ghostly face or trypophobia type thumbnail then another 5-10 videos down. in no way are they highlighted as sponsored and I find it hard to believe that Google with it's search skills and other far more relevant videos in the results can be returning these videos as results!