Challenging SSD Partition problem... kinda stumped. No volume showing

Upgraded to an NVMe drive a while back, but realized I left some data on the previous SATA disk,

When I connect the SATA disk now, it has no drive letter, which is puzzling. Disk Management sees the disk, and it is online, and shows as Basic, and "healthy (active, primary partition)", but I cannot assign a drive letter to it.

So I go into Diskpart, and I can see the disk, I can query it and see its partitions. The Primary partition is what I want to access, and I can see it in Diskpart, but there are no volumes. I've used Diskpart successfully to assign drive letters before, but only to volumes, not partitions.

I can successfully select the primary partition and make it active. But I still cannot access it.

So I'm kinda stumped.

Can I assign a drive letter to a partition?

Berton said:

Definitely, in Disk Management. You can also Format it but best not to do that until sure you have no further need for the data on it. Every drive needs at least 1 partition to be of use.

Thanks! I forgot to mention its greyed out in Disk Management. Hence why I went to Diskpart

Can you post a screenshot of disk management?
Disk Management - How to Post a Screenshot of