My lighting automation uses Insteon currently. My primary req is that they are smart and connected without needing a central controller o a connection to the internet. My switches all understand lighting scenes and can manage those in a P2P manner, without a central controller. The central controller is primarily used when I want to add actual automations vs. scenes. Even the central controller aspect works 100% disconnected from the internet though. I can easily layer on top any automations I like. For instance, I have my exterior lights driven my the angle of the sun. Then, on top of that I can add internet based triggers for automation as needed. This is where I add in voice assistant triggering of automation and scenes.

Edit: Just to add, very simple binary automations are even possible without a central controller. Like, I have Insteon motion sensors that trigger a lighting scene when they detect motion. These are super simplistic though.