Screen blanks, now camera no signal

Love this monitor, have had for ten years. Since lockdown I've been working remotely and heavy use of display and video camera. I connect to 2018 MBP (USBC) via a dongle to the original octopus plug.

About a month ago it flickered a few times. Then last week the screen starting blanking. Unplug/replug fixed it. Today the camera offered no signal to video apps, though the green camera light came on.

After researching suspect the cable or dongle might be flakey, so my first step is to try a direct USBC - thunderbolt connection . But now with the camera trouble I'm wondering if something else is failing.

Any thoughts?