For this guide i'd be using RE4UHDUltimateTrainer by Raz0r which is a mod from Nexus designed especially for Resident Evil 4, back in older days i used FluffyManager5000 trainer but since the latest patch it stopped working for me and since there arent any mod replacements anywhere easily accessible i had to look for another way for me to wear the Jacket.

I'd recommend for anybody to try Fluffys mod first since installation is relatively easy and it might work for you but i believe its outdated at this point but i am linking it either way.
https://residentevilmodding.boards.net/thread/507/

Unfortunately the RE4UHDUltimateTrainer is also... well, kinda outdated and it doesnt support the newest version of Resident Evil 4 HD and if you try to launch it it will crash your game everytime, so in order for it to work we need to re-download the version 1.06 of Resident Evil 4 and then patch it with 4GB patcher + Microsoft Visual C++ which is all provided in additional files required when trying to download the mod.

Now you might ask ... "Wait a minute, isnt it a bit too much of an effort to just .. wear a ♥♥♥♥♥♥♥ Jacket?!"

Well... yes, unfortunately RE4 is a bit of an old game at this point and people doesnt really make mods like they used to but i coudnt give up because i wanted to re-experience everything yet again and i really didnt wanna play without it, positive side-note is the mod work along with the cutscenes (with some exceptions where Leon has to interact with his knife) and it offers much more than just changing the skin.

Download RE4UHDUltimateTrainer from Nexus
https://www.nexusmods.com/residentevil4/mods/32

and without having to elaborate too much unlike one person on the posts if you click on it, basically what we just need to do is download the older version of RE4 and copy-paste it into your Steam/steamapps/common/Resident Evil 4 then download the 4GB patcher and the distribution package (C++) which all of it should be provided for you.

First what we need to do is create a shortcut for the steam and type -console in the "Target" section right at the end of it
https://gtm.steamproxy.vip/ugc/1701787040302037921/A3EDB2C6EF670841D4273A3C134442C42390AD2F/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

once done close off your steam and reopen it using this shortcut, you should have a console tab next to your profile, type "download_depot 254700 254701 7608705427663292112" (or rather copy paste it lol)

now go to C:\Program Files (x86)\Steam\steamapps\content\app_254700\depot_254701 and wait for both folders to reach 11 GB by checking the size of them and copy-paste all of it to your main game directory.

Now install C++ Visual package and patch the Bio4.exe with the 4GB patcher and thats pretty much it

The mod also allows you to disable the ammo drop from enemies which might result in more survivalist style providing more challenge, make corpses stay, allow you to use kicks from F1, F2 (F3, F4), edit your inventory, change character (yes you can play as Ashley if you like) remove Ashley as a companion so if you dont like her around, and many more feel free to experiment on it its pretty fun.

But i need to warn you playing as HUNK and trying to use any other weapon outside of his TMP and attempting the neckbreaker will crash the game or using Wesker Thrust punch, basically anything which wasnt meant to be used outside of Mercenaries mode by these characters will result in game crashing with some exceptions. (Krauser can use pistol for example)

And if you wonder why does this guide look so primitive i'd say its actually my first time writing one and English isnt my native language either but i hope it might help somebody eventually at some point.

Feel free to ask questions and i'll answer them.