I have an Xbox One X with a external SSD where I keep games that benefit from the speed. They weren’t staying up to date even though I had the other settings on.

I missed one setting that was powering off the SSD do it couldn’t downlooad updates:

When Xbox is off, turn off storage: Unchecked (only matters if you have games on an external drive).

Credit to Reddit for this post that led me to the answer. I’ve updated the locations of these settings since the menus have changed in the past year.

Under System > Updates

• Keep my console up to date: Checked.
• Keep my games & apps up to date: Checked.

Under General > Sleep mode & startup:

• When Xbox is off, turn off storage: Unchecked (only matters if you have games on an external drive).
• Sleep mode: Standby (not Energy saver)