I have tested this FW and it had no effect on the KP I experience.
I have basically retired my TS3+. I bring it out for every point release of Catalina and test on my 16” and my 2016 15”. So far I get a KP within hours.
So I figured out the problem with the flickering. I changed my displayport version from 1.2+ to 1.2 and the problem went away. TBH with sidecar at my disposal I never dock my 16MBP but if you are experiencing flickering I would suggest toggling through your monitor settings.
I’m running 1 4K in clamshell, no problems. Can you at least get a single display running. I’ve had to unplug my dock once because the display wouldn’t wake from sleep, definitely software bugs.