Catalina gets resolution wrong when HDMI switching external monitor

I've been using my MAC with a HDMI splitter to share a 4K monitor for a number of years. I've ever had a issue until the last 2 supplementary release of 10.14.6 Mojave where it seems resolution and control of the monitors got all mixed up (see my previous posts). The fix to Mojave night shift resulting in high cpu (as the kernel tried to change resolution every 1ms) was to upgrade to Caalina or turn off night shift. Indeed Catalina did fix the kernel issue however now with Catalina I have a separate issue. Normally the 4k monitor runs at 60hz and 3840x2160. However, with Catalina, if I switch the monitor between the MAC and windows and then back to MAC when reconnecting to the MAC it selects 30Hz and a resolution that is much lower than before switching and large fonts. The only way to get the resolution back is to completely disconnect the MAC, wait 30 seconds, and then plug it back in. Kind of defeats the purpose of HDMI switching but.... This particular issue did not happen with Mojave or High Sierra so it appears Catalina specific. Anyone aware of any settings that could address this behaviour?