Ill start, for me its gotta be Monster Hunter World on my retroid pocket 6. Even at low settings this game still looks beautiful. Using game native it runs at around 30-40 fps. Ill probably lock this at 30 for stability but this is a surprisingly great experience.
Audio is very important to me. So, when I first heard the less than stellar built in speakers of the RP6 I knew it wasnt gonna cut it. So in place of that im now mostly using the Koss ksc75. These are a bit of a legendary recommendation in the audiophile space because they cost only 20$ and sound absolutely incredible. The sound is very airy and open, which makes them particularly immersive in games. Plus the silver color matches my RP6, and the whole psp/Y2K aethstetic as well.
Its certainly not a seamless experience yet, but its sort of a magical feeling when you get a full on PC game working great on a small handheld like the RP6. Ive been using game native mostly, and for the games I want to play (indies, jrpgs) this thing knocks it out of the park, and for the heavy weight stuff I can local game stream from my desktop PC. This thing is really awesome