Consider an equivalent amount of money spent (say $50k), where any money not going towards the car is donated to eliminating environmental problems (like 5k Prius and $45k spent sequestering CO2 at current prices). Car would be used for average developed-world use: commuting, groceries, random trips, ~15k miles / year.

Should I further elaborate that in the question?

The impact of co2 is a smokescreen. Destroying grounds and mining for minerals for electric batteries can impact the world much more then a million kilometers driven with a gas gozzling super truck.

Co2 of electric energy and heat production overshadows cars by an insane amount.

Considering micro particles from the tires, a diverse range of oils, wiper fluids, particles from the brakes and recycling of all control boards, plastics and foams, they are more concerning than co2 output. At least to me. Causing an accident and having your car burning out would ruin all previous considerations, no matter what type of car.

Having a car that breaks down often, that is technological to involved for proper repair, like hybrids and evs, will wreck all previous considerations. You will plug out components and put new in, effectively producing involved trash and buying your car again over time. You can of course be lucky, or you can buy the ongoing repair problem.

So basically the cheapest car, considering all costs, including repairs and recycling and governmental taxes, would be the best in the long run. This is hart to predict and everyone has that problem, when deciding on a car to buy.

Taking any old giant diesel Mercedes limousine, that is already run for 30 years, for a 1000$ upgrading it to lpg or ethanol and using it for another 30 years, could be argued to be far more environmental friendly than any new electric car or hybrid.

If direct co2 output is your only metric, it will be the cheapest electric car you can find. Just don't crash it or drive it in way that causes lots of repairs.