So on that note, I got very bored in a zoom call this afternoon and designed my own! It has a variable prime duration, inertia switch, a warning light connected to both inertia switch and alternator, , uses the alternator to detect if the engine is turning (I know the fan belt can snap but it would be good to know that too) and uses switched 12v so that it has no way to trickle drain the battery. I can throw it together with components I already have so let’s see how well it works!