Ah <3 Upspin! It's been a minute. I've personally read through & love Upspin. I always found solid a little too tied to RDF & the semantic web push. The solid project is/was super valiant effort, but these days I feel like the semantic web push peaked with HTML & schema.org.

> By storing the data on my personal device and (presumably?) paying for a managed relay (and maybe an encrypted backup), I can keep my data in my physical possession, but I won't have to host anything on my own. Is that the idea?

We're hoping to give that exact setup to app developers (maybe that's you :). We still have work to do on encryption at rest to keep the hosted server "dumb", and more plumbing into existing app development ecosystems like flutter, expo, tauri, etc. but yes, that's the hope. Give developers tools to ship apps that renegotiate the "user social contract".