Cheat Engine

[doom3007]

So I did pass the cheat engine tutorial, and I even doubt cheat engine itself (moving to ArtMoney for other salvation)

My goal is pretty simple, finding a value and editing it.

I have some experience in cheat engine over all, edited in many games and had experienced several issues (as a value being hidden by xor or some type of multiplication in some games)

But this time this is something strange,
steps I've taken

Unticking fast scan, value type is All (before you judge me, cheat engine version is 7.3, also tried to search with ArtMoney)
Searching only by Unknown initial value and then unchanged and changed values. (Ofcourse after normal numbers didn't work out)

Tried using also HxD and made a save, used an item, saved again, comparing the save file caused actually almost completely two different save files (Only same 'signature at the beginning of like 4 lines and ends with the same 4 bytes)

I'm assuming there's some kind of encryption / unknown xor or an other type of storaging system, might be functional programming, avoiding storing on ram the values..

I am pretty lost here, thing is this game is a game of a man I know and not a known one.

Trying to avoid debuggers for the meanwhile.

Now I know I might missed something big, I am a noobie in some way..
But do anyone have any idea how can I test it and try to make it pass easier?

I am not trying to develop a hack, just to edit a value once and for all.

It's the gold count and damn that got me off guard of how hard it is.

If anyone has ideas, please help, sorry if its not the section, it said General Gamehacking I thought that's the closest to it.
Also didn't see any help format really.
I tried though searching in the forums here for any 'same' problems, but when I see any, they just did what I did and removing fast scan for example or making more types (I did all) helped them.

Thanks ahead!!