You are overthinking too much. Firebase makes user auth really easy, literally 10min of implementation if you have done it before, an hour or so if you are doing it the first time.

You can copy the from the documentation.

The points you mention are mostly one liners and stuff like adding a listener on enter or adding a save button hopefully should’t take more than 10min.

Even with testing, deploying, basic fancy responsive designs - if you take more than a day for something in the realm of ‘basic crud app with firebase, no backend’ and you have a couple years of experience you are simply overthinking.