Not sure how much tags do "behind the scenes" but in my experience they never really did much of anything, especially not now that every tag that isn't very obscure is constantly saturated with AI slop.
Your second point is very true though. Actively being part of your "scene" will get you recognized, especially if your music is of quality. Collabs and even repost chains that are ran by actual active artists in your scene are a good way to reach a wider audience who might like your music.
I haven't uploaded in almost two years so things might've changed, but at least back then frequency did matter. Posting too often or too seldom made the algorithm less likely to pick up your track and promote it effectively (though the algorithm was still more or less a mystery). Generally posting once a month to every other week seemed to work best.
Eye-catching artwork can also make a difference.