I agree that those are terrible programs to have preinstalled but so is Steam

KDE turns on do not disturb mode when a program is in full screen mode by default.

You can test this by binding DnD to a button (preferable Meta key + unused letter like F), opening a program in full screen mode and toggling DnD.

This feature can be disabled in settings.

Last I used Ubuntu you do indeed get an ad every time you apt upgrade You can still go into some config file and remove it though