Most appropriate file storage locations

[lovetox]

Hello,

I am maintaining a chat application and i am not sure where to store particular files

Image/File Downloads -> My plan is to create a subfolder /Downloads/MyApplication, and store everything there

Chat Message Database -> Where would i store this if i dont want it to be deleted when the app is removed? Usually Users dont want to lose the chat history just because they remove the app for a time. More importantly it should be on a easy to reach location so the user can backup this data or move it to a different machine. I tried to get the cap Unvirtualized Resource but it was not granted.

Encryption Keys -> The application supports end 2 end encryption, and therefor we need to store the keys somewhere. Again these keys should not be deleted if the app is removed, otherwise on the next install the identity of the machine would change because we need to regenerate the keys. Its not just one key, which we could store somewhere in a credentials vault i assume, its a sqlite database.

I tried searching the net for some clues, but didnt find any pointers if there are appropriate storage locations on Windows for these use cases.