How to update a Dell server when the Dell Server Update Utility ISO is 11GB?
You can use Dell Repository Manager which will allow you to download drivers/firmwares for specific server models.
It will allow you to export these drivers/firmwares as a bootable Linux ISO image, burn it and use it to update your servers.
Alternatively you can export the drivers/firmwares as Dell SUU (Server Update Utility) packages to some directory and copy it to an USB storage media. Then plug it in your server, start your server, press F10 during POST to access the Dell Lifecycle Controller and from this UEFI interface you will be able to update your firmwares.