Lots of good suggestions. There is no really wrong answer. What’s best for you is going to be circumstantial.
My older rig doesn’t have an M.2 option. It’s setup as:
OS: dedicated ~256GB SSD
Games: dedicated ~512 GB mSata drive
User Profiles, etc: ~3TB Mirrored HDD
if I upgraded, in my budget, I’d aim for 1-2TB M.2 and large SSDs for local storage of profiles. A bit like:
OS: Approx ~250GB partitioned M.2
Games : whatever’s left on m.2 and new partition
Profile Data: Mirrored SSD, largest I could afford
My older rig doesn’t have an M.2 option. It’s setup as:
OS: dedicated ~256GB SSD
Games: dedicated ~512 GB mSata drive
User Profiles, etc: ~3TB Mirrored HDD
if I upgraded, in my budget, I’d aim for 1-2TB M.2 and large SSDs for local storage of profiles. A bit like:
OS: Approx ~250GB partitioned M.2
Games : whatever’s left on m.2 and new partition
Profile Data: Mirrored SSD, largest I could afford