ZenHAX

I changed the locres file to change the language of the medium game
And I converted the changes to a pak file with u4pak
But when I move it to the paks folder and run the game, none of my changes apply (this problem exists for a few other games I tested)
please guide me

First: I don't know which version are you running, but in my case, all of the .pak files start with "pakchunk". So the naming of your file seems wrong.
Second: Check which .pak file is the last one (sorting via name). For example: in my case, the the last .pak file is called "pakchunk100-WindowsNoEditor.pak". If I name my created .pak file "pakchunk101-WindowsNoEditor_HUN.pak", it works.
Third: the directory structure is wrong in your .pak file (see the screenshot). No wonder the game(s) don't recognize it. The correct structure in this case would be "Medium/Content/Localization".