I’m aware that IP bans inconvenience users who did nothing wrong. But I feel like this can be alleviated:

• make the IP ban temporary. The idea is to force the spammer to get another IP or give up, not to use the IP itself as the enforcement.
• IP-ban only account creation, not activity. So even if you’re using the same IP, as long as you already have an account, you should be unaffected.

But… well, we’re back into “lemmy needs better built-in mod tools” territory.