One could go for the Rimworld concept of an ideoligion. I think I’ll quote the relevant chunk of the wiki page below; some of the stuff is about game mechanics, and the world depicted in the game is, ah, brutal; but the description is pretty comprehensive and reasonably applicable.
An ideoligion consists of many separate aspects to customize:
Primary
Structure—What deities (or lack thereof) that followers believe in. Examples include Abstract theist, that “gods are formless and everywhere”, or Christian origin, which is closer to the Abrahamic religions of the west. Structure helps determine the randomized names and lore of your ideoligion. This is almost entirely cosmetic, but can add a few ritual options.
Memes—The basic beliefs of the ideoligion. An ideoligion with the Cannibal meme will definitely enjoy human meat. Each ideoligion can have up to 4 memes. Most memes do not add much on their own, but affect what precepts the ideoligion has and cannot have. Some memes have access to role specialists.
Precepts—What a follower’s belief systems are. Precepts directly determine how colonists will react to certain actions. An ideoligion with Cannibalism: Preferred will have followers enjoy eating human meat. An ideoligion with Cannibalism: Required (Ravenous) will want to eat human meat for every meal.
Certain precepts have statistical effects beyond mood. For instance, Drugs: Essential boosts drug crop yield, synthesis speed, and sell price. These tend to be locked behind their associated meme.
Secondary
Rituals—Special occasions, from Dance Party to Animal Sacrifice to Funerals. Every time you do a ritual, you can end up with a good or bad outcome. Good outcomes will increase colonist mood, and come with a special, defined reward. For example, a spectacular festival can give you a random recruit, or cause a gauranlen pod to sprout.
You can increase the chances of a good outcomes by following the ritual’s requirements. A funeral can be done without your colonist’s body, but the quality will be increased if present.
Roles—Every ideoligion has a Leader and Moral Guide. From there, you can have up to 2 types of specialists. A Shooting Specialist will be great at ranged combat, but is unable to do many types of skilled work. Note that you can have as many specialists of a specific type as you want. For example, you can have 3 Shooting Specialists in a single colony, but cannot have a Shooting, Plants, AND Research specialist in the same ideoligion.
Relics—Ideoligions can have relics. Relics can be either Legendary quality weapons or specific types of items that serve no other purpose. Relics must be found from a specific, multi-part relic hunt quest, which can take many years. Having a relic present will cause a number of benefits.
Buildings—Buildings used by your ideoligion: altars, sacrificial flags, etc. Largely used for rituals. Altars and the like will eventually be demanded by followers of your ideoligion.
Preferences—Ideoligions can prefer apparel, weapons, and xenotypes, as well as venerate specific animals. Colonists will like having/being around preferred items. Whenever a colonist will dislike a non-preferred item is dependent on the preference in question.
Descriptive
Styles—How buildings made by an ideoligious builder will look. Largely cosmetic. However, it interacts with the Diversity of Thought precept. If colonists are neutral or bigoted, then they will enjoy being near styles of the same ideoligion. If colonists appreciate Diversity of Thought, they will enjoy being near styled buildings that their ideoligion could not make. Certain styles will affect more or less buildings.
Cultures—Roughly where your ideoligion comes from. Astropolitian represents those coming from space. Corunan represents tribes in general. Entirely cosmetic.
Lore—A randomly generated description of the ideoligion, based off of memes, structures, cultures, etc. Entirely cosmetic.
Icon / color—An ideoligion’s icon is used whenever an ideology will be displayed. The color of the icon will be a preferred color for followers. Followers gain a +1 moodlet for wearing their ideology’s color, or their own favorite color. All colors require dye and the same amount of dye.
One could go for the Rimworld concept of an ideoligion. I think I’ll quote the relevant chunk of the wiki page below; some of the stuff is about game mechanics, and the world depicted in the game is, ah, brutal; but the description is pretty comprehensive and reasonably applicable.