I'm unable to change these permissions even though I'm a Super Admin
Hello @next7itabqpipe ,
As I said in other topic https://www.googlecloudcommunity.com/gc/Cloud-Hub/Service-account-key-creation-is-disabled/m-p/73610...
You must have assigned Org Policy Admin OR Org Admin IAM roles, to be able to manage organization policies. Look at my screenshot, console showing which permission you don't have it.
cheers,
DamianS