So I'm not sure how you handle the separation of snapchat and onlyfans content, but I'll give some of my thoughts. From a camsite member's perspective, it can be a bit confusing and even annoying when models when models are spreading content to multiple different places. I think most members would be content to just have access to all of your content in one place and to only pay once or on a monthly basis. So it could be a good idea to just consolidate everything onto one platform, but it's hard to say because I don't know what kind of money you bring in across your various platforms.
Member retention could be a question of how often you're uploading content. If people feel that you're not posting enough then they will probably leave. I have stopped tipping for premium snapchats in the past because I felt the model wasn't posting enough content to justify it. Basically, there has to be a reason for users to want to stay subscribed. That will probably come down to the content (does it meet their tastes/expectations, is it distinct enough to warrant another subscription/monthly tip) and frequency of content.
So, perhaps try to do a poll or something with your members/friends. Ask them what type of content they would like to see more of. Experiment a bit. Maybe things will work, maybe not, but at least you tried something.