For some reason or another, I keep gravitating towards these Asus Ally vs Steam Deck videos that are making the rounds over YouTube:

The talk about controls came up and it made me think of what I'm doing for Tetent. I've also been annoyed that I've got everything except the (in my opinion) seldom used joystick button. 

I'm taking advantage of the fact that, unlike with Tetent, you can't actually use the joystick AND buttons at the same time, and I'm putting the joystick press on the end of the Tetrinsic active area:

I've also corrected the position of the XYAB buttons. If you were looking at Tetent from the top, the layout shows the left side of Tetrinsics. For TrueGame, the left side would have left, up, right, down instead of X, A, B, Y. I can't find any actual numbers, but I'd imagine that the order of most to least used of the 4 buttons is A, B, X, Y. Like with Shift, there's some force between position 4 and 5, and 5 is "spring loaded" as if it was a button perpendicular to the sliding axis.

Replace Joystick Button, Analog X and Analog Y with Left Click, Cursor X, Cursor Y respectively and there's some kind of Steam Deck trackpad alternative.