Welp I think its good enough. I will still do some tweaking on it since I feel like stealth could be a bit louder but I have to find out how to do that since the scripting cant go above 1 so for now I am messing around in audio editing software to fix it later.
I hope this'll work for you as well as it worked for me and I hope you'll enjoy it!
I'd appriciate any comments about things I could fix or make better.

This mod of course requires CustomOST.
Link here : https://modworkshop.net/mod/27359

Put the folder in to "CustomOSTTracks" folder.

Music preview:

Stealth music preview: