So is this monitor not compatible with MacBook Pro's from 2020 and if not, why did it work for a while but not now?

I've made sure my macbook pro has the most up-to-date software/securities. The Dell monitor works with my husband's PC. That would rule out my HDMI cord and adapter being the issue. I've plugged my macbook pro HDMI cord into my Sony TV and it works as an extended display like the Dell monitor used to. The adapter I'm using is: USB C Hub HDMI Adapter for MacBook Pro / Air Swith and Other Type C Devices, USBC Digital AV Multiport (6 in 1 Dongle with Ports of typec USB 3.0/4K HDMI/SD/TF Card Reader) Type-c Multi Docking I've unplugged and plugged HDMI cords, power cord, adapter, etc. Then just yesterday I tried all the tricks that have worked in the past, but nothing made the monitor connect with the MacBook Pro. Then a few days later the macbook pro got where I had to restart it to get the monitor to work. For a few days I could unplug and plug things back in and it would start working.

Then, all-of-a-sudden, I started getting the 'no HDMI signal from your device' message on the monitor. Dell monitor S2721H not connecting with MacBook Pro - says 'no HDMI signal from your device' My S2721H Dell monitor was connecting with my 2020 MacBook Pro for weeks with no issues.

Jud380 hdmi not working mac