You actually think that "syncing onto a mac" is the same as sending the data to a completely unvetted 3rd party cloud?
Apple can only allows EU-based alternatives. Then the data protection is solely in hands of the EU commission and their vetting and regulation.
Problem solved. Next question?
"I own data that may be stored on Apple's servers. Apple's operating system syncs that data to my local computer in a secure fashion. Apple's operating system exposes low-level APIs that allow other applications to access that data. I can install third party applications. Those third party applications can access that data and may exfiltrate it to an unvetted 3rd party cloud."
Your turn smart guy: Am I talking about iOS or MacOS?