Why so extreme, I believe they only will have to stop providing their premium iCloud service to the UK as this is the one that have E2E encryption and thus would be affected?
Is that even legal? At the very least, doesn't it break some EU privacy laws?
Only real move way is to start creating local corporate structures. Maybe even entirely separate companies. And have the infra in those areas. So UK customers are served from UK servers by UK company. USA customers from USA servers by USA company. And EU customers from EU servers by EU company. Repeat for enough.
Maybe if some of these agree to play fully nice with legislation and privacy there could be some cross work. But seeing how even EU is moving, I am doubtful.