Plutonium

Install Lutris's flatpack via Discover
Use this install script https://lutris.net/games/install/30919/view to install the wine prefix with needed dependencies
Open the recently installed Wine's configuration, and set all of the xinput library overrides to builtin, native.
Add Lutris or the recently installed Modern Warfare 3 to Steam as a non steam game
Play in game-mode, steam deck controls should work (hold Steam button and use touch pad to move and click mouse)
For MW3, for calling in killstreaks, one could add a radial menu to the left touch pad to press 4, 5 and 6.

Beware of installing other apps in the wine prefix (like steam), it could break xinput for some reason.

A list of waypoints can be found https://github.com/ineedbots/piw5_bot_warfare/tree/master/raw/maps/mp/bots/waypoints

There are a few members of the community submitting waypoints to the project over time.

And Bot Warfare is completely external to any of the stock gamelogic, so any unexpected behavior not related to the bots is something outside of the mod.

I run the Bot Warfare Dome server as a testing stage for the bots, so feel free to join that and see what they are like.

If you'd like to contribute waypoints, have a look at https://github.com/ineedbots/piw5_bot_warfare/blob/master/raw/bw-assets/wpedit.md and https://github.com/ineedbots/piw5_bot_warfare/issues/6

Custom GSC functions

And GSC functions to control testclients; botAction, botMovement, etc.

If the developers do not want to do it, I have it already implemented on my T4M fork
https://github.com/ineedbots/T4M/blob/master/t4m/PatchT4MP.cpp#L370

Its more of a proof of concept and not production code

Cool work!