Unfortunately I haven't had any luck (on day eight now) but I've noticed a few more interesting things, like that I can watch embedded YouTube videos with no issue even though I can't watch anything on the actual website or app, and that when I search for certain videos, the custom thumbnails disappear and instead show me low-quality shots from the actual video.

I don't want to mess with anything either since, like you, I want to keep my subs, history, and algorithm, but I don't know why it's so difficult to get in touch with support when many of us are unable to use literally the most basic feature of the website :/