GOG's installers are made with InnoSetup, you can use a tool like InnoExtract to get the files out of them (source at https://constexpr.org/innoextract/ or in MacPorts/Homebrew).

IIRC they can be extracted using innoextract: https://github.com/dscharrer/innoextract

Needs to be used with the offline installer files from GOG

You can uh

find them on the internet.

I wont tell you that the record 2020_03_22_DOOM on archive.org has it. I can't confirm.