If you can generate enough amps , one of these peltier coolers would be very simple. a lot of things use them now, like bar fridges. other than a fan , no moving parts, no gasses to leak , no hoses. unlike a fridge they dont need a separate cooling system.
one drawback is that hey are not super efficient, The real advantage is the simplicity.
here's a link to one on amazon but there is a lot of different ones and different sizes if you look into that.
https://www.amazon.ca/LANTRO-JS-Semiconductor-Refrigeration-Thermoelectric/dp/B094NMHPGJ
it might need a separate battery, wired like in an RV so you can't use up your starting battery with the extra load. you could even charge that battery at home with a charger and it would provide a certain amount of cooling before it ran down. That would be really simple, then no extra charging ability would be needed.