If you look at the URL for the ISO download at https://www.truenas.com/download-truenas-community-edition/, you’ll see:
https://download.sys.truenas.net/TrueNAS-SCALE-Fangtooth/25.04.2/TrueNAS-SCALE-25.04.2.iso
So run through the same procedure again as you did you for update.ixsystems.com, but for download.sys.truenas.net
Clue: download.sys.truenas.net is another CNAME pointing to link.storjshare.io