Have you disabled the iCloud factor between these devices?
Not sure but there are shared items outside the cloud that
work separately when other technologies are not present.
Although clues on how to enable 'continuity' appear here..
• Use Continuity to connect your Mac, iPhone, iPad, iPod touch, and Apple Watch - Apple Support
https://support.apple.com/en-us/HT204681
..there may be some 'toggle points' to disable them also.
For troubleshooting from 'second user' account can be useful.
And startup in Safe mode can re-set certain defaults while
checking them; restart normally will complete the process.
There may be other things to try & do; short of new system install.
{..Further investigations toward this end; not quite an OS reinstall,
could be an answer. The functions presented in macOS Recovery.?}