Umbrel makes it easy on Raspberry Pi. Umbrel will also let you set up your own Nostr relay 😉 I want to do this a well and we're local to each other. Maybe we can get together at some point and compare notes. 4 GB was what I was thinking about for running Bitcoin node and Nostr. I think 2 GB would be just fine for Bitcoin. I was also wanting to do a Bitcoin Lightning node as well