You can render spheres as pixel perfect round spheres using points with the least cost possible without raymarching. But the limit for a stable 60 fps depends on the device at the end, i could render in a test 20 million without issue for sphere based particles on my machine.
I’m quite sure someone already made an example for lit spheres but i can’t find right now i’m on mobile.
Recommend reading that thread and look in the forum as it has been a topic before.