> If anybody has any tips about how to get a better feed, I'm willing to give it another go.
I do. Don't waste time by trying to find the stuff you want by explicitly searching for specific tags (aside from maybe for the purpose of the initial seeding, but that's not a must at all). That would indeed bring up just tons of kinda trashy content that seems like it is tailored to either teenagers or the lowest common denominator. Instead, try using the main feed.
Simply scroll past videos you don't find interesting/appealing to you, hit "like" (double tap) on the kind of videos you like, etc. You've mentioned you've already found some creators you like, that's great. Hit "like" on some of their videos that you actually like . Don't try to trick the algorithm by forcing some unnatural behaviors, just use the feed normally. To clarify, when I say "feed", I mean "For You" feed aka the main feed, not "Following" feed.
First 30 mins or so of that will be meh. But the more you use it that way (doesn't need to be in one sitting at all, that part doesn't matter), the better the content will be tailored to your tastes.
I can almost guarantee that you will not only find what you wanted that way, but also discover things that you didn't realize you liked/wanted to see. I checked out feeds on my friends' phones before, and it is kinda wild how different our feeds are. A friend of mine who is very seriously into bodybuilding gets some crazy useful (according to him) exercise technique/regimen videos that are very far from the mainstream "exercise routine/fitness advice" videos. Another friend of mine who is into building/fixing cars gets a lot of great build project videos. I get a solid mix of a particular type of dark comedy that appeals to me, sound synthesis videos, and some cool electronics projects that I would actually want to attempt myself.
Just don't rush it, don't expect some instant magic to happen, and let it naturally adapt to your tastes.