Update: hypothesis seems to be proven.
When using chrome://flags/ in affected browsers to set
" Insecure origins treated as secure" and entering the IPCameraBinding URL incl. port, i.e.
and relauching Chrome, the MainUI displays fine incl. MJPEG in the widget (verified on Chrome for Android an Win 10). Still doesn’t fix video card, seems to be an unrelated issue, but the widget is nicer anyways…
So, I have a workaround. A clean fix would involve getting the IPCameraBinding to expose an HTTPS connection, I guess.
Thoughts?