Mini PC vs NAS: which one first?
These are not competing products. They are two halves of the same build, and the only real question is which half you need this year.
The rule: a mini PC is compute that happens to have a disk. A NAS is disks that happen to have a CPU. Buy for whichever noun is your actual problem.
Buy the mini PC first if
Your problem is "I want to run things" — Home Assistant, Pi-hole, a game server, twenty containers, a Proxmox playground. An N100-class mini PC (Amazon search, opens in a new tab) idles at single-digit watts, makes no noise, and will run more services than you will ever get round to configuring.
It is also the right first buy if you are unsure. Compute is cheap to redeploy; storage decisions are sticky for years.
Buy the NAS first if
Your problem is "I have data and one copy of it". Family photos on a single laptop, a media library on one external drive, a decade of work with no second copy. That is not a compute problem and no amount of mini PC fixes it.
A two-bay enclosure (Amazon search, opens in a new tab) with a mirrored pair of CMR NAS drives (Amazon search, opens in a new tab) is the boring correct answer, and the reason to buy the enclosure rather than roll your own is that its web UI is usable by other people in your household when you are not there.
The case for doing both badly
You can absolutely put two drives in a mini PC and call it done. Plenty of good homelabs are exactly this. What you lose is expansion — one M.2 slot and one SATA port is a ceiling you hit within a year of running Plex — and what you gain is one less box and one less thing making noise.
If your total data is under about 4TB and staying there, the combined box is genuinely the smarter build. Above that, the split is worth it.
The transcoding exception
If this is a Plex or Jellyfin build, compute choice stops being flexible. You want Intel Quick Sync — a recent-generation Intel mini PC (Amazon search, opens in a new tab) transcodes several 4K streams on a chip drawing less power than a light bulb. A NAS CPU will not do this, and a discrete GPU is a more expensive answer to the same question.
But check whether you actually transcode first. If everything direct-plays to one TV, you are buying a feature you will never use.
The picks
First homelab, no urgent data problem: mini PC. Cheapest route to "I run things now", and it teaches you what you actually want.
Data at risk right now: two-bay NAS plus two CMR drives. Do this before anything else and stop reading.
Media server: Quick Sync mini PC first, storage second — but only after confirming you transcode.
Under 4TB total and staying small: one mini PC with two drives. Skip the NAS entirely; you can always add one later, and later is cheaper.