You leave out the fact that @ruud was already running mastodon.world before all this. So he does have experience running a big instance. He had a team of moderators from mastodon.world that helped from the start.
The influx of people was never a problem, if you choose the right hosting provider you are prepared for these things. And the hosting company we use provides all those tools to help us grow. We started with a small server at Hetzner.de and gradually upgraded when it was required. They have no limits on bandwidth so that is also something Ruud looked at.
Anyway, you have a lot of say about how you would do things but you had a 3 years head start…