The subscriptions plugin uses Stripe.
This offloads most of the work from Discourse.
It’s as easy as you could reasonably expect it could be. Stripe work hard to make things as attractive to the B2B client as possible.
Self hosting is not hard you just have to be prepared to learn as much as you need and do need some spare time to devote to it (but is not remotely a full time occupation!)
If you aren’t prepared or able to put in the time (fair enough), buy a professional hosting plan or pay for someone to help you. Marketplace