This isn't the answer to the RG406H, it's the answer to the Retroid Pocket Mini V2, which looks nearly identical to this and includes a 3.9" 4:3 OLED screen and SnapDragon 865.
The Pocket AIR Mini is the final name of Ayaneo's Code R or Code R-1 project. Launching with a 4:3 display, the Pocket AIR Mini appears to be Ayaneo's attempt at rivalling compact retro gaming handhelds like the Anbernic RG406H.