We've been happily using BuildJet [0] for over a year now.
Saved over $25k in CI costs compared to GH Actions - they're also using super powerful bare metal servers with Hetzner - we got about a 94% reduction in build time!
Absolutely chuffed, good to see more companies on the market though.
You can charge a flat rate of VAT but not per location based upon the EU rules.
If you reach out on the contact form, would be great to discuss your use-case.