Might not be a good deal, usally HP Mini or Dell units have better prices and better specs. You can get those for 100$ with decently modern CPUs, USB 3.0 , USB-C etc. You can find mode models with dual NVME slots, other with 1 NVME + 1 SATA that might be enough for the OP’s use case.
Can you recommend some devices? Most of the ones i saw had good prices, but not performance relative to power usage. The N100 with its 4 efficiency cores is actually quite good for the price and power usage. Unfortunately most mini pcs with it have limited ports.
I also think, that 2 ssds might be sufficient for the beginning. I’m even thinking of just adding 2 external ssd’s and call it a day for the beginning (one as backup), but that does not scale well.
Im using a couple HP T730 thin clients. It has a 4 core ryzen cpu, up to 32gb RAM, and a PCIE x4 port (physical x8). One of them is my firewall, with pfsense and a 4 port i310 gigabit ethernet card. The other is a work-in-progress NAS. I’ve got a 8 port SATA/SAS card and I’m planning on printing a HDD enclosure with my 3d printer.
I haven’t measured the actual power consumption, but I’ve seen claims of 10-20W.