I would prefer to let Bluesky die silently instead of throwing a life line.

As mentioned: It’s not the silver bullet solution but something that raises the bar for abuse. The reputational score is build up over time on the specific server based on the up- and downvotes you received.

So, yes, this can be abused itself as well - but it requires a lot more effort.

People may not like it but a reputation system could solve this. Yes, it’s not the ultimate weapon and can surely be abused itself.

But it could help to prevent something like this.

How could it work? Well, each server could retain a reputation score for each user it knows. Every up- or downvote is then modified by this value.

This will not solve the issue entirely, but will make it less easy to abuse.