How to reset screen resolution on debian?

Question

linux

I have a large monitor and a smaller monitor. I worked on a computer behind a small monitor. On linux and on Windows, the monitor worked as it should, but when I set it to a large one, when I turned on the computer, it wrote that there was no support, turned on windows on it blindly, and Windows was already starting to show. But linux, when loading it itself, everything shows fine, and when Linux loads the desktop, the monitor writes that there is no support.
In general, when switching to a new monitor, operating systems and boot write that there is no support. Who knows how to fix it?

Answer 1

I don't know what DE you have, but, first of all, in the settings of the screens of this DE, try to make not duplication, but an extension of the desktop.