Thanks for providing such detailed information, makes it easier to help you.
Could you do another screenshot of the running processes in Task Manager please - but this time, be sure to first click the button "Show processes from all users" at the bottom.
In your screenshot above, only the processes that run under your user account are visible, but we need to see all of them.
I agree that the RAM usage increase after boot is a sign of a memory hog somewhere. We'll get this figured out.