M2+ SSD SATA or just large M2 hard drive?

Pa
1

I buy a notebook, which has a 256 GB M2 hard drive in it and has an additional SSD SATA slot.
What makes more sense:
Let the M2 in there and buy an additional SSD, or replace the M2 with a larger M2 and leave the SSD slot free?
In terms of speed, all hard drives are equally fast: 560 MB / s.

Ro

In any case, I would leave the M.2 for the operating system and some additional programs in it and then decide depending on their own use needs, if you have a little more very fast additional memory via SSD, or better 1 - 2 TB, for example. Need for an extensive collection of videos, music and games.