Q: New Mac; the local hard drive is too small for my requirements

Forget about that adapter I found on Amazon. It converts a PCIe chip to USB 3. Why didn't they use Thunderbolt? I mean, other than USB is more prevalent? TB would have been a heck of a lot faster connection.

thermal tape which are positioned to contact the two chips in the storage stick,

yes, that appears to be correct.

which transfer the heat the chips produce to the back plate, which is in direct contact with the thermal core

That would be nice, but I don't think it does that. That plate is over the exposed face, so almost all it can do is sit in the flow of air and try to stay cool.

That plate is over the exposed face, so almost all it can do is sit in the flow of air and try to stay cool.

Oh, the plate is from the front side you can see. So it's passive cooling from the bottom to top airflow generated by the fan, not conduction cooling via the core.

OWC has some offerings projected for some time this January: https://eshop.macsales.com/preorder/OWC-Aura-SSD-for-Mac-Pro/

Too slow. It's been linked to twice in this topic already.