One annoyance with Ubuntu 24.04 is the lack of option to change background adjustment option from its default of “zoom” to something more sensible like “centred”. In order to achieve this, users are required to install the gnome tweaks tool:

sudo apt-get install gnome-tweaks

Once installed, there’s an option under the appearance tap for “background” and a drop down “Adjustment”, which can be changed in order to prevent backgrounds doing crazy things, especially with external monitors plugged in.