Your project is a bit similar to mine and I am very curious about how you use Blockstack.

I have been hosting a CouchDB instance myself on a VPN but considered moving to Firebase while prototyping since it seems easier to use. Considering Firebase since it offers offline-first support. However, only today I was made aware of Blockstack and I have seen it mentioned multiple places.

How do you like working with Blockstack and what made you choose it? Does your app work offline? Does it synchronize automatically between devices?

I also want to take data privacy very seriously, since I am dealing with personal and sensitive data (just like a person's journal is very sensitive to them).