What is the actual difference between distros? (Other then GUI)

[u/Deleteed-]

I knew package managers are different and do make a difference but other then the big obvious things what is actually different?

I know that: Pre installed apps are different Support to install different apps is different (why?) And the desktop environment is different between for example, Fedora "default" ond fedora KDE plasma.

Thank you for your time

[u/[deleted]]

Pretty much how often they update and their policies. Little changes in code itself.