Ladder logic, written by peasants. (signed: control peasant that prefers ST)
Lucky you, my stakeholders would run screaming for the hills whenever they caught a whiff of written code on PLCs. All ladder, all the time.
A fart has been lofted in your direction
Would I? The amiga setup sounds totally fine to me. Aside from old HVAC equipment potentially wasting a lot of energy, I see nothing wrong with using a 40 year old computer to control everything.