Well, like I mentioned, I found out from my accountant that I can stick with 2019. I'll just make sure the OS doesn't get updated to the point where I can't use QB 2019 anymore. 

And, when the day comes that I can't use QB, I'll switch to GnuCash, or whatever else is available at the time. 

If QB doesn't want me as a customer—and it very much appears from the way they treat me, and what their reps say when they chat with me that they don't—then fine. I don't have to give my money to people who don't want to sell me what I want to buy.