It seems Apple have added support for shipping alternate browser engines in the EU, and could in theory be sold using Apple's own store there, as well as third party ones:

https://developer.apple.com/support/alternative-browser-engi...

FWIW, it does look like Apple have made it pretty hard to qualify to ship one though! To best of my knowledge, no one has actually shipped one yet in the EU.

> https://open-web-advocacy.org/blog/apples-browser-engine-ban...