Can't connect to external display after updating to Monterey 12.4

I've just updated my MacBook Pro to Monterey 12.4 in order to install the latest version of Keynote (v12.0). Typically we run the keynote presentation on the Mac with a thunderbolt to HDMI dongle, then to an Analog Way Eikos 2 switcher, which then allows us to send the display to our projector.

Since updating the OS, our switcher can not see the display output. I've been reading that others are having trouble connecting to external displays with the new OS. Wondering if anyone knows a solution?