Review say no problem…
“Aside of a review about the game itself, I'd like to share about mod support of this. First, GOG version of Fallout 4 binary (Fallout4.exe) is virtually same as Steam version except Steam stubs. It even requires steam_api64.dll to run and GoG version has steam_api64.dll but it is a wrapper of galaxy client API. It means...
GoG version has same bug that Steam version has. You will get darker face bug with some texture replacers, nvidia gameworks related crash on RTX 3000 series or later and goes on. In short, yes GoG version has no problem to use with F4SE.
However, if mods are not working correctly, check fallout.ini and change or add following line in [ARHCIVE] section: bInvalidateOlderFiles=1 sResourceDataDirsFinal= Then all the mods can be used right away.
Note to "Buttout" f4se plugin: Use "OnProcessAttach" for LoadMethod in "xSE PluginPreloader.xml"”