It's quite an accomplishment for an individual. You might find the Pine A64 interesting. I got 6 of the 512MB models for $15 each. [1]

I plan on running Kubesolo on them since 1.0 was recently released.[2]

[1] https://pine64.org/devices/pine_a64/

[2] https://github.com/portainer/kubesolo

Cool, i wish i had the skills. I'm planning to learn PCB design to build a low power low cost PCB based in the SG2002/LicheeRV Nano design with a MAX17043 battery gauge, gpio buttons and a battery controller like TP4057.

Let me know if you are interested ;-)

That's cool as a project, but I don't really see the point. Everything's hungry for memory these days. DDR3 is a relative bargain. Why not put a socket on there so you can add a cheap 8GiB laptop DIMM?