There are 3-4 Windwheel Asters each location, and you can get around 30 in total.
You can get about 14 Windwheel Asters.
Puzzles, Secrets, and Hidden Chests in Liyue
Cecilia
Hu Tao
Shenhe
Hypostatic Symphony
Puzzles, Secrets, and Hidden Chests in Dragonspine
Primordial Jade Greatswotd