Almost... we could say that the socket
supports an M.2 NVMe
/ SATA

Or should do either, anyway. There's a very slight chance that it somehow doesn't support NVMe, but I think that's highly unlikely (especially with that other site having NVMe drives in the spare parts list).
While you're in there, can we have a photo of the whole insides? I couldn't find one on the web. Still curious about the 2.5" drive situation.
Not sure what I'd recommend buying now! I'm not totally convinced by the Crucial P1 NVMe, TBH, just going by reviews since I haven't had one. Out of the 970 EVO 500GB at $90 and the 970 EVO plus at $117, I think I'd just go for the 970 EVO still, the read speeds are very similar. Another one worth considering is the
ADATA SX8200 Pro at $68 - I was about to buy the 1TB version of it when Amazon popped up with 33% off the 970 EVO making it almost the same price.
The MX500 M.2 SATA at $67 is still a solid choice, but when extra perfomance can be had for not much more...
I dunno!