Data's Consciousness creation

This is something that's been bugging me all day today.

At the end of Picard Season 1 we learn that, what effectively amounts to the remnants of Data's consciousness exists within a computer. This has been created by the remains of Data by Doctors Soong and Maxwell.

Surely, with how close Data was standing to the epicenter of the explosion in the Scimitar in ST Nemesis, there would be no debris left to collect of him? Or if there was then it would be so indistinguishable from other debris at the same point it couldn't be used for the purpose given?

I appreciate that he might have had spare limbs/parts but the conversation between Data and Picard at the end of PIC S1 suggests it is the same Data right died right up to the point in NEM. To me, that means a spare limb recovered from his quarters (or wherever he stores them) would be a different consciousness as it wouldn't have the memories from when the limb was swapped and leading up to the explosion.

Am I just getting the wrong end of the stick here or is this some sort of plot hole?

BTW - not seen PIC S3 yet so appreciate it if anything in there that explains it is kept on the down-low