@achillespilot Hey- I did get it worked out. What worked for me was lr-mupen64plus-next and video at 1920x1080 @ 60 Hz. The N64 logo when the rom launches looks like garbage but the intro and the game itself look great. Good luck!
@red_trev The only thing i can find as of right now is Displaying a single image through secondary port for like a digital marquee on a an arcade but im in the same exact boat if you have never heard of ETA prime he has awesome content and is very informative...
Video here ------>
What game(s) have you tried? It could be a corrupted ROM, so try a few different games or try to find another copy of the game.
Have you tried to remove the redream package and re-install from the latest binary?
Also have you tried using the lr-flycast or Reicast emulators to run the game instead? Both can be found within the optional packages menu. When launching the ROM, hit a button to choose which emulator to use(once you have installed them). All three emulators run well on my RPI4 4Gb at stock speeds.
Only other thing is to think your pi is throttling, have you any heatsinks/cooling? Are you using a case?