You can try and it may work because a lot of games on Steam and Epic barely use the DRM.

I have portable installations of several games from Epic that I moved between Windows installs that just work by executing the game’s binary

The issue with Steam is that some games do use the Steam DRM to verify additional content, but even there are ways to bypass that in two ways.

1. The game files already include the DLC you just need Steam’s license to activate. In this case you just need to crack the DLC.
2. The game files do NOT include the DLC. In this case you could try installing the DLC from a DRM-free source or just copy the missing files from another installation. (This was a way to bypass the limitations of some demos using denuvo, mixed with a mod to bypass integrity checks)