I liked to play DJ Sharpnel maps so that increased my stamina. I also just play more jumpstream and handstream in general. Here's some if you haven't already got them.
The stamina tag usually brings good results on the search tab, but you can also look for mapper like fullcombo, dj sharpnel songs, lv.4 songs and so. (how tf you have 9k pp and funky friday have any influence in stamina at this point, :tf:)