Just want to update here. Fought with this all day on my steam deck. On my desktop build, on arch linux, this worked for me:
For steam deck:
https://www.reddit.com/r/SteamDeck/comments/t8al0i
Need to allow your steam deck to get packages from pacman.
Basically, install wine and winetricks via pacman and install lutris via flatpak.
Download the h2pc_installer_X.X.zip from
http://www.h2maps.net/Cartographer/Installer/
With wine installed, double click the setup EXE and install it as you would normally on Windows.
Follow the video to install wmp10, this is required to get audio working.
Note: if you get an error while trying to install wmp10, I got an error saying "this is a 64-bit wine setup" or something like that, this link will help:
https://forum.winehq.org/viewtopic.php?t=27296
rm -rf /home/(username)/.wine
WINEARCH=win32 wineboot
rm -rf is a dangerous command if you don't know what you're doing, this will completely blow out your .wine directory, so if you have other things you need in there, be weary.
You should install litrus-fshack-7.2, not sure if required, but I installed it for good measure. I didn't do any of the configurations in litrus either in the video.
In gaming mode, if you get a unique identifiers error when signing in, join the discord and request help in the help channel, a dev can help you. It has something to do with steam deck pulling wine 7.0-rc5 as opposed to a regular arch linux build pulling 7.22. Might have something to do with the steam OS image having different mirrorlists for pacman potentially, and wine 7.0-rc5 and gaming mode not populating your identifiers correctly..