M4 Max Studio Connection Issues

I'm hoping someone can point me in the right direction to solve this. I've been a Mac user since 1985 and have never experienced this before.

I just bought an M4 Studio and a Samsung 32" M7 Smart Monitor. I have a Yamaha RX-V385 5.1 Amp. I connected the Studio to the Yamaha using HDMI and to the Samsung using a USB-C-to-HDMI adapter (USB out from the Studio, HDMI in to the monitor). I also have a 45" VIZIO TV connected to the Yamaha through HDMI and to the Studio using a BlackMagic UltraStudio 3G (for color-calibrated video editing). Follow me so far?

When I wake the Studio from sleep, or when I boot it up, it also turns on the Yamaha, which I want, and the VIZIO, which I don't necessarily want. I then turn off the VIZIO manually, but the Yamaha also shuts off. Then the Studio reverts back to 1920x1080 (I select 3840x2160 to begin with). After a few tries of turning the Yamaha off and back on, and the VIZIO off, and resetting the resolution, things work correctly, but then randomly things jump back (resolution, VIZIO, etc.).

I have no idea what's going on. I'm running Amphetamine because the external drives spin down, so I'm not sure if that has anything to do with this.

I migrated my settings and apps from my M1 iMac, so I'm not sure if I need to do a clean install of Sequoia.

Any help would be greatly appreciated. Thanks!

Lloyd