You could try finding changed config files by running:
sudo debsums -ac
Note that this won’t catch all. There are files that packages install and don’t touch afterwards. I my case for example it does catch that /etc/gdm3/custom.conf
was modified to enable autologin among other things.
All decent DP KVMs are very expensive. I got an IOGEAR which is a rebranded Aten. It was also in the same price range. Who knew high resolution needs high bandwidth and high bandwidth signaling and switching is hard…