Many thanks!
It’s hard to move between payment service providers (PSPs) if you don’t want you’re users to have to enter their cvv again and go through SCA again. PSPs are reluctant to help you export your users’ cards to another PSP (obviously because they’ll be losing out on your payments then). However, most of them should have some kind of export process if you manage to get to the right support person.
You could use a card proxy service like PCI Proxy if you know you’ll be using many different PSPs or move between them a lot, but they charge a fee for each proxy call AFAIK.
I’ve heard that https://www.paddle.com/ is useful for handling tax across multiple different countries.
Build various products and used multiple payment providers. While Stripe and Paddle are the best ones, you can also use PayPal, Gumroad, LemonSqueezy etc. too, to accept payments, but they don’t perfectly fit this use case.