Read the info and download the Python script found at https://mp.uu.se/en/web/info/stod/it-telefoni/it-support/network-on-campus/eduroam/linux.

The installer puts the certificate at /home/cat_installer/ca.pem by default. Since the /home directory might be protected, it is recommended to move the file elsewhere. Create a file named eduroam.8021x in /var/lib/iwd/ and fill in your username and Password B, as in the example below.

# /var/lib/iwd/eduroam.8021x

[Security]
EAP-Method=PEAP
EAP-Identity=anonymous
# If you run the wpa_supplicant CAT installer
# the default location is /home/cat_installer/ca.pem.
# If /home is protected, make sure to move the .pem file, for example:
EAP-PEAP-CACert=/etc/ssl/certs/ca.pem
EAP-PEAP-Phase2-Method=MSCHAPV2
EAP-PEAP-Phase2-Identity=<abcd1234>@user.uu.se
EAP-PEAP-Phase2-Password=<passwordB>
EAP-PEAP-ServerDomainMask=radiusauth.uu.se

[Settings]
AutoConnect=True

If anything is incorrect, iwd will respond with Operation failed.

There seems to be some troubles regarding DNS. I use resolved and it does not let me use certain DNS providers.