If you can’t set different backgrounds for dual monitors on Windows 11/10 use this workaround or free tool to set different wallpapers. The first solution here is to get rid of all desktops ...

Many of the wallpapers are available in sizes all the way down to 320x240, so if you find a multi-monitor wallpaper you love for bank of monitors you may be able to find it for your cellphone too.

Can't understand why Windows doesn't have better built-in dual monitor support like this. DisplayFusion is a free download (donations requested) which requires the .NET 2.0 runtime to run.