UseFixedXACT is a hack that improves sound quality. As it's a hack and doing things unsupported by the API it may not work on all systems. That's why it's optional. Linux already has improved sound quality over the Window's version so it isn't needed on Linux.Please remove the hard dependency on Discord Game SDK, if I remove the DLL the game won't start with the mod applied. I am not interested in any Discord integration as I don't use it and don't want it to create unnecessary connections.
There's a config parameter to disable it additionally, but it would be nice to not require a DLL that is never going to be used depending on the configuration.
Additionally, I found that UseFixedXACT breaks cutscene audio on Linux/Proton, any version I tried (8.x, 9.x, Experimental and GE) had the same result of no audio and a silent pop a second into the playback.
Also, on the linked website I could find version 5.3.1 of the mod, please update the OP.
Finally, is there any difference between using unpacked Steam executable vs. GOG executable? The warning dialogue mentioning LAA patch specifically addresses "the steam executable for SR2" being unstable.
All does LAA increases the memory available to the game (it almost doubles it). It eliminates errors due to running out of memory and means housekeeping routines aren't as essential to keeping the game running smoothly. I believe Windows apps running under Wine already set the LAA flag.