@mitu This help request can be closed out. I ended up uninstalling retropie and Ubuntu and put Batocera on my SSD. Batocera seems to be more user friendly in terms of initial installation and settings. From what I've read Retropie has more options/settings but my emulation needs are simple and Batocera serves me well.
Additionally, after hours of messing with this, when I plugged it in today it was magically working. I had just rebuilt the box after an issue with SSD corruption. I'm still willing to pull data/test to help anyone else who has come across this issue. I also plan on rebooting a few times to see if this is a fluke.
@melbmatt50 i did - both links are instructions for “headless” (no screen) set ups. you just need to plug your sd card into the pc you used to the write the image and create files in the /boot/ partition.
@radji Ran into this while I was researching my own struggles outputting dual monitors from my Pi 4. I found a way to get it done - I'll spare you the walkthrough if that's okay but it involved booting the desktop environment first with xrandr installed and the displays configured there - then rigging the thing to autostart emulation station from there on top of that environment. Long story short, I took a huge performance hit, even the gen. 4 consoles started dropping frames and chopping audio. I was super proud to get it working after many failures and posts online saying it couldn't be done, but unfortunately it just wasn't worth it in the end. Most people suggest an HDMI splitter and now that I can see how rough it can be on the system to make this work - just don't do it is my advice. Maybe it's a moot point for you by now, but FYI for anyone else down the road. Go with the splitter.
I had an issue almost the same as this. I have a pi4b with a 7” touchscreen. When I plug it in to my tv it starts fine color burst and command line show fine on my tv and the 7” screen together, but as soon as emulation station starts the picture goes away and only the sound comes through the TV. If I go into command line or pixel desktop the picture comes back on the tv. After a couple weeks of frustration I figured out if I take the power off the touchscreen everything will work perfect on my tv.