Private inbox page and email alerts for my Firebase contact form

Hi, I have a small photography website in Dutch (HTML on GitHub, the contact form saves to Firebase Firestore). The form was fixed last month and every message now saves correctly. Two things are still missing.
- A private page where only I can log in and read all messages, newest first, and mark the ones I answered. Right now I have to open the Firebase console every time and on my phone it is a nightmare.
- An email to my own address every time a new message comes in. I already missed an event and a print request because I did not know a message was there.
Please do not touch the layout or the photos. Everything the visitor or I see should be in Dutch.