I think that any solution via script involving IPs, and firewall changes could have side effects on the network. Most of the stake blockchain networks are designed to work with one BP due to the complexity that represents having multiple potential duplicated blocks at the same time being transmitted to the network.
I’m not 100% on what happens in Cardano when a duplicate block is sent using a cloned BP, but I assume that one block will go and the other might create a fork and be rejected at a later time. Any how, my point here is that there is a reason there is not an official config to do this, meaning is not designed to do so.
I’m not trying to discourage innovation, just giving feedback. I know that for example, Solana had some sort of backup producer config that it acts like a active-pasive system, they both are in sync with the network, but with different status flags and maintained a heartbeat between them to determine who should be promoted to be the active one, but, they ended up discontinuing it cause it was buggy.
MO