Zone Based for 6-8 zones?

Trying to understand what the threshold for if/when to use a ZBF vs a traditional firewall no longer makes sense. At the moment I have 5 zones, but am looking to add a 6th, and realizing how many rule-sets/zone-policy sets I now need to create.

There is no steep threshold.
It’s more being fed up with too much rules having source or destination subnets in them