Lowly US workers would seem to have a slightly better chance of a secure life if the US democrats could get and maintain a majority, and it would be an opportunity for more meaningful change.

Unfortunately the Democrats won't do anything meaningful that can't simply be undone by the Republicans. They also had many chances to make a better change already, and yet they didn't do that either. On top of that, while their rhetoric may be different, a lot of their policies are actually really similar, if not the same. Did Biden ever free those who were imprisoned by the US-Mexico Border under Trump? What about Obama and his 500+ drone strikes on civilians? Is he any different from Bush?

I don’t see capitalism as evil, but it is obviously a successful model that has largely taken over the world.

Yes and no; While yes, Capitalism was a necessary step in overthrowing and replacing Feudalism, it has also come with the exploitation of the Proletariat (Working Class) via the extraction of surplus value, as well as the worker's lack of ownership over the Means of Production. Capitalism in its late stage (which we live in nowadays) has also lead to the destruction of the environment, the alienation of humanity from society (via excessive and unhealthy individualism) and nature, and even the decreasing quality of products (due to a thing called "planned obsolescence)

Capitalism is successful in a sense that it allows the Bourgeoisie (Ultra-Wealthy Ruling Class) to accumulate wealth and power at the expense of the masses.

I wonder if there are viable alternatives that don’t involve pitchforks, along with a transitional path to them.

[...]

I can’t imagine a wholesale abandonment of the current capitalist system, a big revolution, and any kind of stable or fair system coming from it. That whole human nature thing, I guess.

As great as a peaceful transfer of power would be, it is pure ~~schniff~~ idealism, unfortunately. The Bourgeoisie have, historically, employed force to suppress workers' movements. You can't simply talk them into giving up their power. Hence, revolution is necessary to establish Socialism. (or at least its transitional stage)

We also acknowledge that a sudden change from global capitalism into global communism is improbable and extremely impractical. We are not Trotskyists. This is why AES (Already Existing Socialist) Countries still have capitalist elements in them, (i.e. China and Vietnam operate using market economies and have their own private enterprises.) although these capitalist elements will gradually fade away.

As for the "Human nature" argument, while yes, we are quite a selfish species, we are also a social and altruistic species. What parts of our nature get emphasized are the results of our upbringing, socioeconomic conditions, etc., and what matters is that we build those conditions needed for altruism and egalitarianism to flourish. It is only Socialism/Communism, not Capitalism, that can build those conditions.