@BettyJaneB 

Thank you for the reply.  I wish @ReymondO would have been more straightforward with the real answer, just like you have,  instead of just saying: "If you're using QBDT for Mac 2019, the supported software would be at least Mac OS X v10.12 (Sierra), v10.14 (Mojave), v10.13 (High Sierra)."  implying that QBDT for Mac 2019 does not work with Big Sur or it has not been updated to work with macOS Big Sur as it has. This confuses people. The description should have Big Sur added to this list for clarity. I don't understand why it is so difficult to display the real facts when people ask something here.

@BettyJaneB , are the engineers working on getting QBDT for Mac 2019 ready for macOS Monterey in the near future?

Thank you