I like to think there's a distinct difference, summed up like so:

Communism attempts to put the control and distribution of resources (capital) on the collective, ie everyone. Since everyone effectively owns it, it feels like nobody does.

Capitalism puts it on individuals. Nowadays, almost all of these individuals acquired their resource(s) by inheritance. If not, by dubious (morally questionable) means.

This is a simplification that may upset people on both sides, but it's about as clean as I can think to make it.

Note: the following is from the perspective of a somewhat average person living in the US.

My personal thought is that the democratic republic political system would ideally be coupled with the communistic (I'd prefer federated unions, ie federations, but speaking broadly) economic one. They seem to be natural matches.

However, it seems the coupling of said republic with capitalism causes significant and repeated backslides on social issues and education. Capital owners, after all, are most interested in maximizing gains while minimizing losses; this has led to a fairly high number of people being convinced to think that education is bad, especially university level education. Which, in turn, makes them compliant voters and eager workers, often severely underpaid. Which they, of course, have no idea of knowing since they likely have never left their birth town.

That's not to say that such things won't happen with communism. They should happen a lot less, but only if we put controls in place to combat abuse and overreach. In other words, regulations. Capitalism...might be beyond hope at this point, given how capital owners have been acting lately.

I don't know what will actually end up working, but I hope we try something new soon. Because this ain't it. Preferably before we extinct more species. Hopefully before we extinct ourselves.

I keep ranting, sorry for the wall of text.