I found this one, for example but I don't know the brand.
The only 2240 SSD of a company I know on Amazon Italy is Kingston, but has the wrong screw placements.
Genuine curiosity - how do you cope without the trackpads on the Deck? They're so useful in game for mouse based games (e.g. No Man's Sky and Guild Wars 2), and useful out of game for fiddly pointing e.g. when in desktop mode.
The Ally looks cool, but the absence of at least one makes it look like a non-starter (not that I'm trying toove on from my Deck anyway).