An OTS NAS with upgradable RAM is a good option for a small form factor. It’s personal preference. I’d prefer to start with something cheap/free like an old PC or laptop and upgrade later as needed. For storage, I prefer the modularity and cost effectiveness of a DAS. But if you’ll only need 2 bays DXP2800 is a good option.

Also, make sure to have backups of important data like photos. Check out 3-2-1 backup strategies.

This is reasonable for a single device. I’m running about that and more on an i7-8700. I’d recommended Intel 8th gen or newer for transcoding. RAM is unfortunately more important, you’ll want at least 16 GB. I’d start with low cost used hardware with a couple SATA ports and you can expand to a better device with more storage or add a DAS in a couple years once this pricing insanity dies down.

Do you have a fallback if solar production is low?

Octave