Trump got less than 50% of the vote, and less than a third of eligible voters voted for him. The real issue is that the two parties have created a situation where you cannot vote for a viable candidate. Case in point: approximately a dozen democratic senators have come out in support of the war. Like, if you don’t want to intentionally bring about the apocalypse/nuclear holocaust, and you live in those states, the only way to avoid voting for those things is to not vote.

You can try getting your incumbent kicked out in the primaries, but that’s a dangerous game in swing states. In your case (WA) you absolutely should vote in the primary for the farthest left democrat possible.

We probably should switch to multi-party proportional representation at some point.

This is the right idea. Under-appreciated is that voting in the federal general elections is the point at which you have the least effect on anything. Earlier (primaries) and more local (all those elections way fewer people go to because there are no nationally-covered races on it) is far more effective at actually affecting the world. Someone who votes in all of those and skips the federal general bubbles is a more-effective voter than someone who does the opposite and only votes for the big federal offices (and those are the only ones people will commonly shame you for skipping, which is really backwards)

More voters 55+ will have died in a year (~2M/year) since he was elected to office than was the margin of victory. High single digit percentage points of eligible voters who did not vote. Ahh, well, it is what it is. We take the world as it is, not as we wish it to be.