Thanks for the kind words and the bookmark!
You're right. Since I use SQLAlchemy, the core is already database agnostic. Swapping the connection string to Postgres actually works for most features right now.
I listed it as "Roadmap" only because I haven't finished the full end-to-end test suite for Postgres yet, and I wanted the default "Quick Start" to be a zero dependency SQLite setup. I am also working on native read/write splitting so that the system can properly leverage scaling architectures (like Amazon Aurora's single-writer / multi-reader clusters) out of the box.
I'll make sure to clarify in the docs that it's currently "experimental" rather than missing. Appreciate the feedback!