How do I permanently disable personal voice sharing and call sharing across iPhone 16 and iPad?

1. iPhone 16 and iPad. Personal voice will not stay switched off - share across devices - no matter how many times I switch it off on both devices. Apple users have been complaining about this for years. Troubleshooting just doesn't fix it.
2. iPhone - share calls across devices will not stay off either. I spend everyday switching it off. Surely when switched off it should stay off. These headaches raise questions about device security and privacy. Software updates are not fixing these problems.

[Re-Titled by Moderator]

Original Title: NOT Sharing Anything..