I said that the SDD is removable, not that you'll be able to remove by yourself. It's the technical support that will do this and this with these locks.
If the PS5's SSD breaks you'll need a completely new board, with the SeX the technical support can just replace the SDD and restore your board. It's cheaper.
There's no confirmation if it's removable, but just simply
looking at the shot, it certainly seems like it'd be removable in a way not requiring de-soldering. I can't remember where I read it, but someone either on B3D or Era talked about the clamps at the side possibly being able to get pulled to lift the top part off, and slot in another compatible drive.
That and when you look at the board shots for Series X on MS's website, when they get to the SSD part, you can see something over the SSD keeping it slotted in place. It's not an x-clamp, but some type of clamp. And it clearly looks like the SSD is housed in that compartment bay (at least from the shot I am thinking of).
Really wish I could find the post in particular that touched on it, it's convinced me that most likely, the internal drive might be replaceable. But it'd need to be a custom replacement, not simply any old drive could slot in there much less be outright compatible. And that's tying back into some posts on how the XvA might be working WRT memory mapping a couple of posters on B3D went into (which I linked a long time ago in the Xbox Velocity Architecture thread) that could be the reason they needed to use proprietary drives in the first place.
FWIW, IIRC MS manufactures the actual drive and its internals. Companies like Seagate are building compatible enclosures to house the drive components, which are compatible with MS's spec. I think it's fair to speculate the internal drive could be replaceable, but it's prob best to treat it as speculation rather than confirmation until official word is provided (and even if so, I don't know if that'd mean "replaceable" as in the end-user could just replace it themselves).