I have 2 external displays with HDMI cables, I connect to HDMI/USB-C adapters to my MacBook Pro (2018). They worked great, then I upgrade to Catalina. Now when I connect them, they work for 10 seconds, and then go black. I am not mirroring. Windows opened on the displays, are not moved to laptop display when they go black, so it's like the Mac believes the display is still there and working. For some reason, it worked for 2 solid hours this morning, but after I returned from lunch, they just stay working for 10 seconds.
I've followed every piece of advice I can find. When I go to privacy settings for Screen Recording, I don't have an app displayed for me to check. I've shutdown and restarted. I go to sleep, and then wake up. I unplug and plug back in cables. Nothing works for more than 10 seconds.
I'm using Lenovo L24q-20 and LG displays. My HDMI/USB-C adapter is StarTech.
Help! I can't wait until a patch becomes available.