You are correct - it hasn’t always been this way. But it is now unfortunately.
For the record I have an incessant habit to work these things out, never wanting to cave to what shouldn’t have to be done.
But this thing has broken me. I have tried turning off every single option that stops one phone potentially talking to the other to no avail. I’m nearly more angry with myself than I am with apple.
Folks. Trust me. Make a new ID account and concede it’s the only way you’ll seperate work/private completely, but still keep the other great things apple does offer.
I gave up but I won.