I wound suggest looking into Saikey. Probably not as independent at Subscribestar/Patreon as they are a publishing company. But it seems they've worked with similar projects like yours.
Viewing post in My Sister Intimate Sim [Demo] comments
Thanks for the suggestion!
I wasn't familiar with Saikey, so it's great to learn about a platform with such high flexibility.
I just launched my SubscribeStar a few days ago, so I plan to stick with this for a while. However, it's reassuring to know about options like Saikey for the future.
It would be very helpful if you could let me know if you have any trouble using SubscribeStar.
Thanks again!