I’m really sorry to hear this. If someone wants to target an instance and create enough work so it becomes impossible to maintain it, they can.
This is why we need to spread out on many different instances. Maybe you have noticed that every time Lemmy.world is attacked, there’s almost no content anymore. We can change that by spreading out and posting from different instances.
If a few of them are attacked, then it doesn’t affect the entire fediverse.