Nice catch Rrt26en5. I installed NINA Version 3.2 RC2 (Release candidate 2) and now asi6200mm Pro (and ZWO EFW) work!
I had to fiddle a bit - uninstall current release NINA, reinstall ZWO ASCOM Camera driver, plug/unplug cables, reboot, and power cycle Camera/EFW; otherwise camera and EFW showed as "offline".
PS: The Camera is only 1 week old. It took some time to purchase a 2" 7-filter set and then install EFW on the camera. I did my testing with a ZWO Canon adapter and Canon EF f/1.2L USM lens on my workbench (no vignetting from captured images). So glad I didn't try to debug this from my outside telescope. Also, nice to know ZWO tech support was quick to reply and ready to follow up as needed.
Thank you.