I tried the fix for the RAM problem in EAW in this thread, but it created a new issue.

EAW runs fine, but when trying to run FOC, I get the following error:

Unable to locate the installation path of Star Wars: Empire At War. Cannot launch the Force of Couruption Expansion!

Does anyone have a solution to this problem, other than renaming the exe file every time I want to play EAW or FOC?

reinstall clear game. Do not install any lobby-mp\lobby-mp+x64\x64 updates, cause they already implemented. At least, in a way required to play in on Win7x64 (they made for WinVista\7). Any firther support - only in Steam, more updated version. But not 100% copatible, just new improvments on MP and Steam Workshop. Do not expect perfect compatibility with Win10.

(there is no compatibility between stean\gog versions, for multiplayer use GameRanger)

So, if you dont need Steam function and Steam multiplayer - you be good with GOG version as it is.
Maybe installing some mods optionaly recommend pathing exe file - but it should be done by special x64+4GbRAM pathing tool (general for any exe).
Should be existed ones - on mod sites. Most of them is GOG comptible caus made on DRM-free exe. Better do it for yourself to ble sure that it is 100% GOG exe compatiblitiy.

MP_lobby+x64 update is for retail only, probably still have DRM. And it is two differ updates - do not believe that one patch is compatible with both. One if for EaW, another is for FoC. They should be labeled (update file name) like that and should be installed twice.

It is for latest variant. LucasArts update it few times. From "vista patch" to two differ "mp lobby + x64 update".
As result - there is a lot of wrong info online, even on disney support site. Latest path variant is separate for EaW base game and FOC.

Did you find a solution?

Oki, I came up with a solution.

Copy sweaw.exe somewhere outside of the game installation directory (f.e. your Desktop). Rename the newly created copy to swfoc.exe. Move the new renamed copy back to the GameData folder. Now you have both sweaw.exe and swfoc.exe in the GameData folder.

That's it. So when you want want to start the OG game, you can do it from the newly created swfoc.exe within the GameData folder and the expansion from the executable within the EAWX folder.

Cheers