I'm not sure I understand the question. Let me try though. I fitted the 256GB NvMe SDD and installed Windows 10. That became Drive C. That all went fine.
Then a few days latter, I bought the ITB SATA SDD drive and fitted that where the old SATA HDD was. That became Drive D.
I redirected the downloads folder from Drive C to Drive D and then that was that. I formatted Drive D to NTFS before I fitted it, I think....if I remember correctly! Does this help to answer your question or have I been silly and forgotten something important?
I can't see anything wrong with that.
Out of interest, are the drives encrypted?
It might be advisable to put the drive in a caddy and see if it behaves.
Alternatively/additionally see if the manufacturer of the drive has a utility program to test it and if there are any firmware updates.
eg
https://semiconductor.samsung.com/consumer-storage/support/tools/