Welcome, @anon47976160,
In List view, there’s a Hide menu where you can toggle on the fields to see as columns there:
Last modified by doesn’t exist. The other two you mention I see are toggled on in your second screenshot. Did you try scrolling your List view page horizontally to see those columns? Or you can drag them higher within the menu to make them appear closer to the left to see without scrolling.
Hope that helps,
Larry