The blank page is what you'd get if you cleared your Watch History. I use this to watch a new-to-me topic/channel or just a video that I know I'd only watch once and don't want in my recommended history in Incognito mode(although you could just remove that video manually from history too).

This makes it easy to somewhat steer the algorithm, I just open and scrub through a few videos of the same "kind" that I'm interested in and this then makes the youtube homepage a bit wieldy. This still populates unrelated videos but at a lower rate.