SSD Backup with MAC Timemachine

Can anybody please offer me some advice and guidance please?
I have a new Mac Mini which is fitted to a Minisopuru vertical Stand & Docking Station.
The dock has a built in SSD slot and I want to use this to do my regular back ups.
I don’t know anything about SSD cards but have used a WD Elements hard drive with Timemachine on another computer.
The Mac Mini has storage of 1TB so I was thinking of buying a 2TB SSD.

I saw online that another user had fitted a WD Blue nvme ssd but that does not mean much to me.
Can anybody advise me on what to buy please?

(I am a bit of a novice on this so any Techies please go easy on me).

Hi @TedS ,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting:

Thank you.
This was picked up by Mario A at Customer Service and Support.
He suggested a couple of options and gave a bit of advice.
I bought a WD Black SN850X NVMe 1TB SSD.
This fit fine and after a bit of fiddling around with configuration, formatting etc it seemed to work fine and has just done its first back up on Timemachine.
Good job, I am grateful.