as long as you aren't specifically discriminating against religion, i dont think it would be an issue. so if you are banning all public gatherings with more than x people, then you cant really argue that the law is discriminating against religion. there's a landmark case rom oregon that goes into that. peyote was an illegal drug but people of some specific religion said peyote use was a ritual, and so the law was anti-religion. SCOTUS said that isnt the case
https://en.wikipedia.org/wiki/Employ...ious%20ritual.
now perhaps if you could prove that the specific way that they banned public gatherings was meant to target religion... ie we are banning all public gatherings held in buildings with ceilings this high and with painted glass windows (or something less ridiculous than that), then you'd have a better case