Basic Windows 95-era GUIs made with standard Windows APIs still look broken.

If you’re trying to for 10-15W targets you might as well wait about a year so you get those options cheap on the market. Even if you pick something like a 35W i3 system today from 10th gen or so it won’t waste more than 10W while idling.

Head over to https://www.servethehome.com/introducing-project-tinyminimicro-home-lab-revolution/ and check their reviews on those machines. They’ve a ton of information.

If you’re okay with spending a bit more power both the HP EliteDesk 800 G6 and HP EliteDesk 800 G4 as they have two M.2. slots. There are currently very good prices for those second hand in 35W configurations.

Read my other comment for other options or an upgrade path for more hard drives on those systems.

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.