Does this also mean that e.g. EU business are not allowed to use Stripe or PayPal, since those are owned by US companies? Or, that it's not good enough anymore to use a EU hosting for Mixpanel or AWS or DigitalOcean?
This would theoretically apply whether using AWS hosting (even in EU availability zones), Stripe or PayPal cart checkouts, or any other platform owned and/or operated by a US business or its subsidiaries. It isn’t relevant where those US-owned data or servers are hosted.
This unfortunate situation could be corrected by the US signing a new treaty or other law that ensures that the US governments, law enforcement, and courts cannot compel US business to violate GDPR.
(I am not your lawyer, this is not legal advice.)