Apple seems to have implemented quite some measures to make alternatives to the AppStore as unpleasant as possible. Even europeans will loose access to stores if they are out of EU territory for undefined periods of time, as per https://support.apple.com/en-us/118110

If you leave the European Union for short-term travel, you'll continue to have access to alternative app marketplaces for a grace period. If you're gone for too long, you'll lose access to some features, including installing new alternative app marketplaces. Apps you installed from alternative app marketplaces will continue to function, but they can't be updated by the marketplace you downloaded it from.