Logitech C270 webcam configured for 1280x720 @ 30fps ... apparently after installing The Spaghetti Detective it seems it keeps the video device busy such that OctoPrint can't initialize it for high-resolution output. I've disabled it and I'm again monitoring my prints (regretfully only locally) in glorious 1280x720 widescreen.
Thank you @PrintedWeezl for tagging me!
@DodgeDeBoulet Yes this is a known issue. I gave more details in your original post : Adjusting webcam resolution