You're skirting around the issues, as Apple just won't allow you to get out of their system in the key parts. Any of the alternative you describe are just clunky workarounds with utterly broken parts (local backups through a Mac have severe issues compared to cloud backups)
> You can also sell your iPhone and get a different phone if you don't want anything to do with Apple.
If you come to that conclusion, it's basically the answer to your "How am I handcuffed to Apple?" question. If you need to give up the system to properly manage your backups, it's pretty much a situation where you're handcuffed or not, with no clear negotiable middle ground option.
> You can also sell your iPhone and get a different phone if you don't want anything to do with Apple.
If you come to that conclusion, it's basically the answer to your "How am I handcuffed to Apple?" question. If you need to give up the system to properly manage your backups, it's pretty much a situation where you're handcuffed or not, with no clear negotiable middle ground option.