Ok, can confirm that... I was able to copy from Steam... a certified, finalized SH4 set up... that included it being ran the 1st time... (through Steam) SH4 v1.5 unmodded virgin copy.
That said, there is another step needed, to get that copy... game guts copied then dropped into a folder set up in C:\ (& NOT in either of UAC's watch dawg territory, either...

) in the following manner.
In C: do the following... (create new folder & name is "Games". (minus the " marks, mind you...

)
In that folder, set up a new folder & name that "SH4". (Again... minus the " marks, mind you...

)
In this folder, ear mark a new folder, aptly named, "pristine-SH4" (by now, shouldn't need to say... minus the " marks...

)
After that's set up... drop paste the guts from Steam's SH4 copy, into pristine-SH4.
A subsimmer, named of Alx... did up a SH4.exe, that could be dropped in to replace the original SH4.exe, & as with Bl!tkre!g's SH3 Steam divorcer kit, bypass having to have Steam, to launch SH4.
Not sure if that is still available to find or not.
A work around may be... if you have KSD II or Niume's reworked KSD II, named KSD II: Ace... you may be able to use its .exe from it.
4, like SH3... (which was released in '05...) is 2 years behind 3, & likely... considered as Ubi does with 3... not worthy of their time... in essence.
Take that.. with a grain of salt.
I do have a more detailed work up, for staying inside of Steam's purview... but is late here for Me & am seriously tired... have stayed up beyond My capabilities & am fighting to stay awake to type this...
I can message after grabbing some z's.. & explain that outline, in more detail...
M. M.