I wonder why you’re accessing your VM from within such a restricted VM?
What version of Plex Web are you using exactly? When I’m squeezing my browser to a 1024x768 window, and create an overflow of columns, Plex will simply add a scroll bar to the table view – all columns still show in their original width, no truncated dates etc.
The only overflow I see is e.g. with titles – and they show a “mouseover bubble” with the full text.
As for resizing columns… there’s already an existing suggestion to address that: