But legitimately using lots of bandwidth isn't the same as a DoS attack. Try and remember that bandwidth isn't the only resource being used.
> Scaleway
In my experience they throttle your CPU usage after a while.
> Hetzner requires you to buy traffic, but there it costs 1$ per 1TB of traffic, which is 1000x cheaper than Firebase.
At no point did I suggest using Firebase was a good idea. I said it's always cheaper to run your own services in the long run, and that they'd have found out their own problems (see my first reply) sooner.