2024 ASUS Rog Strix G16, Back up questions and adding a second SSD.

[JOE.G]

Hi, I have a 2024 G16 Rog Strix with a 1 TB hard drive. I have a 256 GB SSD drive sitting in a draw, I'll post the link to it below. I know this is not a super fast one and smaller than my main but could I add it to the Laptop and use it to make an image/Back up of my main HD and maybe just use it to store photos as well. It has enough room to Back up my main drive.
Or would I be better of getting an external for back up and maybe add this one just for storage?
https://www.amazon.com/gp/product/B09GFZCQJD?tag=snbforums-20
Thanks