You can use the above images to extrapolate that the drive is removeable.
The panel marked SSD in the top image is an EMI shield that snaps onto the SSD cage using small beveled points that line up with matching holes in the cage. The cage is soldered to the board, but the lid is removeable. You can pry this off with a simple part separator tool or a screwdriver if you're a savage. Lots of laptops use shields just like this to kill electrical interference from other components. Those EMI shields come apart the same way. Here you can see a similar design on the left with the same beveled tabs that line up with matching holes.
Under that EMI shield is the SSD itself, mounted like a typical M.2 format drive with a single Torx screw holding the far end of the SSD down. Both the SSD and the Torx screw are visible in Microsoft's own console renders.
Do you have a link to MS confirming you are allowed to remove it and where is the list of compatible SSDs?