Capitalism will happily bake in externalities if anyone makes them.

‘Late stage capitalism’ right now is way less ugly than ‘any stage USSR’, for any sane comparison.

Regulations are not capitalist, definitionally free markets do not account for externalities. Only when an externality has such an effect that it affects market behavior, but then it stops being an externality. Again, definitionaly.

Full capitalism and full communism are not the only options. Not sure why you even brought that up, as I never claimed communism is better? I said capitalism is flawed.

lol. I think you’re thinking Anarchism, not Capitalism.

Capitalism is ‘capital makes the rules’, not ‘there are no rules’.

The problem is you are talking about orthogonal concepts, ie. economic policy and social policy. See the Political Compass: https://www.politicalcompass.org/

Not really, no, since all these mentioned political philosophies have explicit market elements.

Or do you think it’s possible to have a socialist or communist gov’t AND capitalism or free market at the same time?

Because those quite literally are incompatible as part of the definition.

Same as a heavily regulated economy or state ownership of production in Anarchism.