Thanks for the suggestions regarding the proxy service. I will look into. So far, clearnet seems to still be the standard when one needs a to serve a web service to customers.

Yes with Sovran_SystemsOS and the Sovran Pro there is nothing to install (server end). It runs out of the box. So it is simpler to set up then Umbrel. No terminal needed.

We walk the user through opening up ports on their router. So, they get one-on-one attention with that.

Yes, correct the user will still have to learn how to use the frontend software on BTCPayserver, Wordpress, and RTL (if they wish to use Lightning). However, this is the same as using any other custodial company as they have their own proprietary user interfaces the customer has to learn.