I stopped using the realtime database once firestore was released in beta. So haven't experienced the downtime you have demonstrated in the status graphs, but Firebase's SLA [1] for realtime database apparently guarantees service credit for monthly uptime less than 99.95%. To corroborate your observations, check if you received this credit:

Less than 99.95% but equal to or greater than 99.0%: 10% credit

Less than 99.0%: 30% credit

[1] https://firebase.google.com/terms/service-level-agreement/