This is cool! I fully get the appeal of texting for journaling as I did that a lot with Signal. For a while now I have been working on a different way to capture this text yourself-powered journaling with my app tetr. It acts as a standalone app but employs a similar texting-based journaling system where you can set regular messages to be sent to you (even with stuff like checkboxes for routine tasks). It’s also offline-first so data stays on your devices (and will employ e2ee sync once that’s out).

https://tetr.app/