Good news, maybe?  I've just updated my Mac to 14.1 -- the newly released version of Sonoma -- and my copy of QuickBooks 2019 has started to work again, after having failed under 14.0.  I can log in, open a company book, make changes, and sign out.  I have no idea what's going on or for how long it's going to continue, but so far so good?  Hearing about other experiences with this would be great!