I have nothing against your personal preferences. But maybe compare today’s Ubuntu vs Fedora. It would be a much more fair comparison.

My question is simple: Which of these security features are not enabled/present in Ubuntu that give Fedora an advantage?

SELinux has a functional equivalent called Apparmor that is also enabled out of the box in most distros.

What security stuff/mitigations are added on Fedora that are not on Ubuntu?