Before I sealed up my AC on my 300D I briefly considered an under the dash evaporator and blower combo. These are available on Amazon and eBay for chump change. You basically hook them to a compressor or if you’re really interested in a bolt on wart you get an electric compressor and beef up your alternator.
It occurred to me as a temporary possible solution to a leaky evaporator.
I have a vintage unit like this in my pickup and it will freeze your legs off. Powered by a Sanden 5. I would be stunned if a swamp cooler could get close. So if I was going to bolt some kind of wart in my car I’d bolt one of these under the dash and connect it to a Sanden. It’ll kill all aesthetics but at least you won’t roast.
Vintage version in my 65 Ford pickup.
Modern version.
https://jeepair.com/products/under-dash-a-c-unit-for-universal-applications-including-hot-rods?variant=32067015442517