Silent Hunter on the 'modern' computer and OS can be a bother, and is does not matter the source of the game, whether Amazon or Steam or Ubisoft, they ALL default to installing the game in the "C:\Program Files (x86) \..." folder. My Steam install is "C:\Program Files (x86) \Steam \SteamApps \common \Silent Hunter Wolves of the Pacific". My Ubisoft is "C:\Program Files (x86) \Ubisoft \Ubisoft Game Launcher \..." The Amazon install is probably similar, though I do not recall their specific install path. But those paths are where you find the "SH4.exe" file for changing the "Properties" of for High DPI Scaling, etc. spoken of by several of the posters here. The link that Rhodes gave you in the other thread (
Running older games on Win10) is a really good find. Amazon's install would be similar. It is best if you install the game in a folder of your own creation, especially if you are going to add a mod to the game, since Windows will stop any changing of the files in a Program Files folder.
I would uninstall what you have again, then run the installer again, and when it shows the path it wants to install the game to (C:\Program Files (x86)...), just change that path to "C:\MyGames", or whatever name you want, so that you would not have Windows getting in your way. The Amazon app does make a short-cut, but it usually does not "point" to where you want, and changing the Properties gets rather involved with several "Find Target" moves in File Explorer. With this, all you need to do is open File Explorer, open your new MyGames folder, and start rooting through there, finding "SH4.exe", then set the "Properties" as described in other posts. You will have to experiment, since no two computers seem to handle things the same...