I have installed Ubuntu Budgie 26.04 and Fedora Budgie 44, yet I am encountering persistent issues with the bottom dock. When attempting to drag application icons onto it, the dock vanishes. Furthermore, I am unable to alter the desktop wallpaper, as the right-click function remains unresponsive. Dragging folders to copy them onto the desktop is likewise impossible. The situation has become exceedingly convoluted.
Right-click on an open space of crystal dock - choose Edit launchers. Drag and drop onto the dialog.
Alternatively, run the application, right click the icon in the dock and pin the app.
You change desktop wallpapers via budgie-control-center - backgrounds. You can add a picture to choose another wallpaper that you have in your home folder.
If you want to create files or folders on the desktop - open the file-manager, choose the Desktop folder and create files or folders.
Alternatively this Tip from jlib is excellent