I got curious and tried to look up all the different religious emojis. After Judaism (with 14.8 million Jewish people per Wikipedia), from what I can tell the next smallest religion with an emoji is Sikhism, with the khanda: 🪯 Wikipedia says there are 25-30 million Sikhs, so I guess somewhere between ~15 and 25 million? Big hurdle for an upstart religion to overcome.

Although that doesn’t seem to have helped the Mormons, who have ~17 million followers. But I also don’t know of any special symbols they have outside ones shared by other Christians (like crosses).