Thanks, it is enough for me.

Yes, when I buy books on Amazon it’s the dead tree kind.

Yes, KOReader and Librera FD are two applications I use currently.

I’m limiting myself to only open source applications on the tablets. Strictly nothing from Play Store or Aurora.

No, you could never buy books on Amazon, only rent them. Calibre with DeDRM plugin was a poor way to liberate them, given that formatting in libre formats was often worse than the original.

I stopped doing that and ingnored the Kindle ecosystem in general. I tried a Kobe reader with .epub books from diverse sources but I mostly use tablets (LineageOS and GrapheneOS) to consume content these days. The reader apps are not that great there, sadly.

Just use NFS then.

Great writeup.

How much is a kWh in your parts? Noise, ambient temperature? You can buy very decent refurbished Lenovo tiny PCs with some 16 GB RAM and 6 cores and half a TB SSD which will run Proxmox and are low power and noise. You can go multi-node Proxmox later if you want to expand. k8s and related are also an option.

DIY few kWp solar payback is about 2 years.

In Germany consumer power is something like 0.4 EUR/kWh, so economics of running power-hungry hardware might be different. Solar PV might change the equation once again.