So I'm back for support once again. I took a break from the game before playing with this, finally got back into it, did all you said to do, but once it gets to the intro cutscenes/movies/logos before the main menu, it just crashes out to desktop.
The RenX_Mutator_Epic_Units.u is in the CookedPC folder.
I put the .bat with the UDK.exe CNC-Walls?mutator=RenX_Mutator_Epic_Units.RenX_Mutator_Epic_Units into a text document and named it Ephic_Units.bat like you said to, then put that .bat into the Win32 folder and then the Win64 folder, but it crashes in both of them when trying to start it up.
I even went to the github page and downloaded that stuff, but I have no idea where to even put the stuff inside. It also doesn't help there's no videos/installation help for this either for those who are having issues or before they even attempt to do this.
The video I put with my evidence shows how long into loading the .bat/game it takes before it crashes.
So if the developer or anyone who uses this modification or even the moderators could, I think an actual video may help a lot so solve these issues......
Ephic_Units.bat
MedalTVVisceraCleanupDetail20210526161746.mp4