I am wondering is it even possible to get a payment processor for UK LTD (non resident). If there are any that accept non residents I would like to know.
Much more difficult to find nowadays. UK LTDs don't have the best "image / trust" for financial institutions, especially with NON RESIDENT UBO / DIRECTOR.
There are still a lot of providers obviously, but onboarding is difficult especially if you're a "starter".
If you have a proper "setup" (real address, EEA UBO) and in best case some prior processing history you'll be able to find some.