Question about drive setup in Bios

Hi All,
Opened Macrium Reflect this morning and just browsing around and noticed it had my M.2 SSD 250GB drive assigned to Disk 5. I opened Windows 10 Disk Management and noticed the M.2 drive was assigned to Disk 4.
I failed to notice this when I first upgraded to all these new components last year and Installed Win 10 fresh and then added the extra drives. I just assumed the M.2 drive would be Disk 0 or Disk 1 and each of the other Sata drives I installed after would go to 2, 3, etc.
Is this normal for Windows 10 to randomly assign the Disks or did I do something wrong when plugging each Sata drive into the MB?
I think I read something a while back the M.2 drive was linked to one of the Sata connections, but can't find where I read that. And it may not have anything to do with it lol. I may have it twisted around a bit trying to figure why it is displayed like that.
Google is confusing me this morning. maybe I got up on wrong side of the bed hehehe.
Anybody able to clear up the fog in my head this morning?

cheers

M.2 just refers to the form factor of the drive. The communication protocol can be SATA or NVME (PCIe).

The drive numbering depends on the physical connection to the PCH. So if the manufacturer decided to connect your M.2 slot to SATA4 then Windows will show it as Disk 4.

Thanks for the replies.
Everything is running great, I was just curious why the Bios done that.
I forgot to add it was a NVME (PCIe) stick. Installed in a Asus Z270 Tuf Mark 1 MB and installed in the slot that is consealed under a cover.

Note: sorry for posting in General. Should have posted in Hardware.

Greatly appreciated the replies.

Thanks Caledon Ken, Had me wondering when I stumbled on it this morning lol. I will ignore it also.