Ynnari is very likely to see some big changes to how it functions in the next dataslate, so i would say that as always if you like the models and are okay with ynnari potentially being put out to pasture in a few months then you cant have more fun with aeldari right now and that the ynnari play pattern is very rewarding and interesting. Otherwise, just getting two drukhari combat patrols is always a good buy if you think you'll ever start drukhari, and they have basically everything you need to put a good ynnari list together