The easiest way to deal with the usual suspects is to just block the entire countries network range(s). There really is no reason they should be connecting to your home router anyway, and you lose nothing from blocking them.
Sure their packets will still hit your router, but if they are dropped immediately at least you're not wasting a syn-ack on them.
Sure their packets will still hit your router, but if they are dropped immediately at least you're not wasting a syn-ack on them.