When you consider the electoral collage, gerrymandering, corporate lobbying and PACs, billionaires literally writing million-dollar checks to people to get them to vote (for "any candidate", wink wink), and now the Federal Executive trying to put its thumb on the scales by controlling which and how people are allowed to vote, it's really hard to feel like one person voting makes a damn bit of difference.
One person voting doesn't make a difference. That's called democracy. When it does, you've got some type of oligarchy. One person's vote does, however, count. Your complaints are that each of those votes doesn't count equally, and that's valid. "Counts less" still counts though. And the way to fix all that is by voting for people who will fix it. Even if they're not approved by one of two corporations. Once you've lost the ability to do that, which you are heading towards, then you've only got one option left, and it's not a good one.
The US is operating on something like democracy version 0.7 and you guys have refused to install any significant patches for the last fifty years or so. Meanwhile you've let yourselves be propagandized into believing in things like "coequal branches" and election funding as free speech. You're not going to overturn all that with one vote. But if you don't like being responsible for killing kids, and let's be clear, it's a hell of a lot more than 123, you vote whenever you can. Unless you're okay with it, in which case you also vote.