Gyms are created at 2, 6, and 20 total pokestops and gyms in the larger L14 cell. Three is all we can create by submitting Wayspots. There can be more gyms than that if some are sponsored - those don’t have to follow the rules. But sponsored gyms will count as one of the first three if there aren’t already three.
A great article about this stuff: https://pokemongohub.net/post/article/comprehensive-guide-s2-cells-pokemon-go/