Setting the wallpaper with xwallpaper/feh

I want to set a new wallpaper every time I log in.
I’ve done something similar with a different DE using a script in .xprofile which uses xwallpaper.

When I use this on KDE plasma the correct wallpaper appears straight away on login but then gets covered up by the default wallpaper in Plasma.

Is there any way I can stop that default wallpaper showing up?