Personally, I wouldn't build it from scratch. Hive already offers plenty of infrastructure. Also I must admit some of your thoughts were a bit confusing to me but as I was listening I was reminded of this latest offering by @aggroed.
@aggroed/tribes-20-outposts-coming-soon
Though I'm not sure exactly where he's headed with this new project, I think some of what could potentially be offered might be flexible enough to cover some of the things you're looking for. Also, Hive, in general already does some of things you mentioned. The latest hardfork for instance (released yesterday) has a new 'recurring payment' feature. So things like paywalls and subscription models, soon enough, will come standard with Hive straight out of the box.
RE: Ideas for a Social Platform/ NFT Marketplace