>>> upgrading powerbook 5,7 to an nvme:
>>> here is the ide adapter i used: […]
>>> here is the nvme i bought: […]

>> As far as I can see, that's SATA, not NVMe.

> it operates in sata mode. or it wouldnt work.

It operates in SATA mode because it can only do SATA, not NVMe. There is nothing NVMe about the adapter or the SSD.

From the adapter's description: "This product can only use M.2 ngff of sata protocol, not M.2 ngff of nvme protocol."
From the SSD's product page: "Interface M.2 SATA"

Calling any of these anything "NVMe" makes no sense.