Looks great. I was a user of babybuddy[1] and one the pluses was that I could self-host and be in control + had an API. Now that last bit was a bit overkill.
It had one feature that's maybe essential and that I'm missing here, and that is being able to share the app and data with your partner so both are in control of monitoring, maybe I'm overlooking it but I can imagine that's hard to integrate with a PWA that does not use accounts.
One last thing: "no accounts", but filling in the email field is mandatory, i'd skip that.
Nice job!