All of the sudden new dock appeared on my main screen. I think it was caused by something like KDE Plasma update (I didn't read the whole prompt :D). Now I have a default dock at the bottom of my screen that I don't know how to delete and it don't appear that it is added by Latte dock as it provides different options after right clicking. See the screenshot bellow:
Is it posible to show opened windows from other screens on the new dock? I have a setup where majority of my work is done on the primary screen but the dock is just on the bottom secondary screen.
I believe yes, the first thing to do is to follow the wiki page I copied above and go to the section where it explains how to manually create/add a Dock.
From there it is possible you may need to open up its settings (dock) to make sure it displays opened windows from other screens. I hope the option exists, I will check later to make sure.