I second all of your statements. I don’t care if my Apple TV is on WiFi, but my gaming desktop is most definitely hooked to an Ethernet cable. I also use a wired keyboard and mouse on it, but I’ll admit I have a cheap wireless keyboard and mouse for my work laptop because I didn’t want to deal with another set of cables on the same desk, and I can’t think of a good solution for both machines to share the same keyboard and mouse without having to switch the cables between them all the time.
KVM switch looks like it could work, since I don’t want to switch a USB switch and then still have to switch monitor input. Just need to find one with both an HDMI input and a DP input.