All important automations should run fully locally. I also find that focused and simple automations are often most useful. When I say simple I mean in terms of automation logic, not necessarily in terms of interfacing devices, which can be tricky at times. Example of simple automations I like most would be switching amplifiers on/off based on audio state changes, switching lights on/off relative to sunset, and switching electric water and floor heating elements on/off depending on energy price.
I mean a good approach would be to just go through Apollo and … copy with bride! Christian did an amazing job with it.