I repeated Alex's steps to get the Steam version to work several times to no avail. Using an older version of Proton would only cause it to crash after the launcher, and while using GE-Proton 9 and the dx8 fix would at least render the game, Protontricks absolutely refuses to install DirectMusic. I'm absolutely baffled by what's going on.

However instead of merely leaving you with another borked report, I'm happy to say the (European) disk version of the game does in fact work for me but it's a long setup if you haven't done any of these steps for other games yet. In VERY short, the steps are as follows: Acquire disk image of the game (bin/cue files) → Install CDEmu on Steam Deck → Install Lutris → Mount bin/cue files using CDEmu → In Lutris, use autorun.exe as installer from the disk → Select Windows XP 32 Bit + 3dfx → Complete the installation process → Download d3d8to9 from Alex's link and place it in the XOM/bin directory → In Lutris, add d3d8=n,b as overrides → In Lutris, run Winetricks, select default prefix - install Windows component and select DirectMusic from the list to install.

After doing all that, the game finally worked for me, music and everything. No idea what the deal with the Steam version is. The game seems to have no disk-based DRM, so it's not necessary to insert the virtual disk in desktop mode before playing. If you have a USB disk drive and the original disk then installing CDEmu is not necessary.