I'm using Kubuntu (Ubuntu) 24.04 and wanted to use eduroam.
However when I tried to configure eduroam in the GUI (network-manager), I got the error message 802.1x connections must have iwd provisioning file
TL;DR You need to configure it manually. iwd also doesn't like external certificates.
PSA: You MUST embed the certificate in the iwd config file. If not, it will tell you Failed to load /home/robin/eduroam-rootcert.pem
even though the file is perfectly fine.
Example config for TU Darmstadt:
Place under /var/lib/iwd/eduroam.8021x