Can't get two displays to sync in Mac mini running macOS Sonoma

Mac Mini 2018, Macos Sonoma.

Using two displays. No problems. Until a couple of days ago.

I then, out of curiosity, tested a few different resolution options. Then this happened. See image.

The screens are same brand and model, bought at the same time. The settings both IN the screens and in system settings are the same. I also use the app BetterDisplay, and the settings there are also identical. Still, the "sync" fails.

Have tested individual and different resolutions on both as it seems as if the left has a lower and the right a higher.

Still no go.

Anyone?

[Re-Titled by Moderator]

Original Title: Can't get two displays to sync