Kai's Steam Deck Koi-Koi Layout! Steam Deck 2 days
combined playtime Designed to be fast to use, & map specific buttons. Right stick & trackpad act like a mouse. Left trackpad covers hand & table region. Left stick moves cursor around the hand, click the stick to change to the table. Dpad navigates the hand & table cards. (Up & down switch between/reset) Hold L1/R1 to show the cards/yakus help screen; use the right stick to scroll. L2 & R2 = click. Pause button = pause & unpause. A = click. B = "Next". X = Koi-Koi. Y = Stop Koi-Koi.
Mouse Inputs Mouse Regions
Mouse movements Steam Controller (2015) about 23 hours
combined playtime Button X=Koi koi, Button Y=Next
Mouse Inputs Keyboard Inputs Gamepad Inputs
delRhode's minimal mouse Generic Controller 3 days
combined playtime Just what you need, with extended play in mind.