Polycom VVX 600 and MFA

It is 2 years later and there is still no workable solution for these phones. It is quite unbelievable when you think that this is (or once was) such a strategic collaboration for MS and Polycom, and that they have not managed to work something out. I am the only one in my office who puts up with checking my phone in the morning and signing in again if needed, so that I can make and receive calls during the day. Everybody else resorted to using their personal cell phones. But we are paying through the nose for the E5 licenses and calling plans.
Now, over the past couple of months, things seem to have taken a turn for the worse. The latest firmware that MS is pushing down (5.8.0.12848) broke our ability to authenticate with the phones ("failed to fetch user certificate"). I suspect that this has to do with MS adding support for Teams and that this introduced a glitch. I now have to pin my firmware to the last one where web sign-in worked, which means that even if there ever is a fix for allowing MFA with app passwords on the device, I will not get it because I cannot allow the phones to upgrade the firmware ..... 
Is there anybody out there who deployed SFB Online with Lync handsets and can claim that it was a success? Or are the people in this thread the last few who are trying to make it work?