"know what you want to watch beforehand" - 100% this. Over at least the past few years, this is almost entirely what I do and it has helped youtube remain a good experience for me. In general, I rarely do research on youtube or twitter or even googling or even reddit. In most instances, I'm better served by just starting with the wikipedia page or some specialized encyclopedia (e.g., Stanford Encyclopedia of Philosophy) and then going from there. On sites like youtube, I either go in knowing precisely what I'm trying to watch or to watch new videos from a select few channels I subscribe to (usually silly stuff like press conferences of football managers etc.).