I have the issue, and have had for a while that whenever I open arma 3 the video settings are returned to default. I change them each time to suit myself (mainly the blur settings), save them and they will stay for the rest of the session. If i close arma 3 and reopen all of the changes are lost.
I think it may be related to where the settings are being saved, as I also cannot name my profiles at all. All I have is PLAYER 1. Again, this is constant.
I only have one settings issue where the game UI gets messed up in relation to the mouse pointer. Changed arma to lower resolution, set UI scale to normal. I restart ArmA and my mouse pointer is not aligned with where I am clicking. Have to go to settings and redo the resolution and UI scale to fix it.
Dont have the other issues reported in the OP.
I found the issue was specific to me, that I had the shell folder paths (User Shell Folders and Shell Folders) were mapped to a non-existent drive in my registry. This meant that the game was trying to save settings and profiles to a drive that didn't exist.
Fixing those paths meant resolved the issue. For more information, I'd suggest looking up "error 1327 invalid drive".