[I work at Firebase :)]

Realtime Database (RTDB) client update latency (in ideal situations) is below 100ms (blazing fast). You could absolutely track the state of the game in RTDB (e.g. players' position, artifacts, etc). You do that using the RTDB SDK and all clients listening to the same document will get updated.

For time dependant events (like bombs) you can use scheduled functions : https://firebase.google.com/docs/functions/schedule-function...

The client setting the bomb calls the function, the function updates RTDB with the location of the bomb and schedules the explosion. 10s later it updates RTDB with the explosion happening.

My 2c