why can't search for fractal higher than 20?
Because your personal Fractal level is not higher than 20, everytime you do fractal 20 it only raised your fractal level by one. So its you’re 4 fractal away from Casual Hero you’d be around 16 I guess. Anyway, look for that when you get in.
You don’t advance by doing fractals below your personal level. Even after doing all different fractals it’s possible that your personal level is only half way.
For example you do 11-20 so your personal level gets to 11. Then you do 1-10 but your personal level is still 11.