To unlock the three preorder outfits Tactical Response, Astral Dive Suit, Urban Response and also the playstation exclusive mission Dr. Yoshimi Tokui's Guided Imagery Experience, do the following:

Get a hex editor and open Control_DX11.exe and/or Control_DX12.exe (make backups first!)
Jump to offset "0145BA9" and change "75 2F" to "90 90". Save the file.

Thats it.

Tested with the current GOG version 41492 (offline installer).

Reference: https://www.pcgamingwiki.com/wiki/Control#Unlock_PlayStation_4_DLC

edit: corrected the offset to the corresponding byte position (instead off the line position viewed in editor)
edit2: removed dead link to nexusmods, added PCGW instead

Opened with Hex Editor online and I do not see the 0145BA5 I do see the correct file number. Which Hex Editor did you use?

Either I do not have the latest version, or something. The file here does not show up anywhere on any hex editor online or installed.

I use Fhred.

Downloaded and opened Control Dx11 and there is no file in there at all that you list in OP

I don't understand your problem... You go to "C:\GOG Games\" (or wherever you installed the game) and open the executable "Control_DX11.exe" or "Control_DX11.exe" in a hex editor and make the edits as explained.

I did that. I click Find and paste the 0145BA9 into the Search. it is not there.
I have the offline installer 41492.

The only number that comes close to the one you say is

00145B80
00145B90
00145BA0
00145BB0

The offsets I have are all 8 digits and the number you have in " is 7 digits. This is using the HxD Hex Editor.
Opening the Dx11. Also tried the Dx12

Sorry, but you really lack the will to figure stuff out for yourself...
Of course the line offset depends on how many bytes are displayed per line in your editor. And the leading zeroes don't matter, 1 is the same as 00001.

Now look in the line with your offset "00145BA0" and you should see the the mentioned values somewhere. If not you do sth. wrong.

Not to be rude, but this is the first time I have used a Hex Editor. and 00145BA0 is not 00145BA9. The Number you gave Didn't Exist! I got it working now, since you said to use the BA0 and not the BA9 ( not there ). If you could have explained better, I would have gotten this sooner. Not everyone can be a Rocket Scientist at Everything. I do thank you for helping me because I would not have figured this out on my own.

So then the GOG version unlocks just like the Steam version?
https://www.pcgamingwiki.com/wiki/Control#Unlock_PlayStation_4_DLC

Yes. I will edit the PCGW page accordingly.

The instructions on PCGW are a bit different than what's posted in the first post in this thread:

1. Go to offset 145B09 (Ctrl+G in HxD) and change 75 to EB.
2. Go to offset 145BA8 and change 75 2F to 90 90

Mainly, the first step is completely missing in the post, not sure why.

Yeah, it's a bit confusing. Maybe the first edit is only necessary for the steam version or is just outdated information (Maybe it's better to make an extra instruction for the gog version)
All I can say is, that only the second edit is necessary and sufficient for all unlocks.

I see. Well I did both changes in the GOG version and everything seems to be in order so far. Do you know if that first step should actually be avoided on the GOG version, or it's just redundant and doesn't affect anything?