Earlier quoted context omitted.
This is unfortunately a common problem and the only way to beat the algorithm is to turn it against itself. Create few playlists and add songs you like to them and also be diligent about liking and unliking songs. These will heavily influence your recommendations and you should be able to get back on track.
Spotify needs to enable dislike on any song playing, not just in discovery playlists.
I have playlists that work as filters for me, if I'm mass copying a playlist I first put it into the filter playlist, then I press "skip duplicates" now all the songs that are not on my shit list (fiilter list) will end up at the bottom labeled "now" on "date added" then I copy those to the playlist I want to and erase them from the filter.