I got it working with the Steam version + Steam's TSLRCM.
If you've already tried to install it then go to the game's main override folder, something like:
[drive]:\[steam folder]\SteamLibrary\steamapps\common\Knights of the Old Republic II\override
If there's a file "kreia.dlg" there then delete it
Next, before you install things you go into the folder "tslpatchdata" in this mod's files.
Open changes.ini with a simple text editor like Windows Notepad.
Change the line "LookupGameFolder=1" to "LookupGameFolder=0", save. That will enable you to point the patcher to a location.
Now you run the TSLPatcher.exe, it will ask you where your game is located. To work with Steam's TSLRCM you need to point it to where that is located, it should be something like:
[drive]:\[steam folder]\SteamLibrary\steamapps\workshop\content\208580\485537937