No, voting for a third party is voting for a third party. If that party gains enough track to become the second most elected, that party can be the winning party the year after.

Also in about every other democracy the concept of coalitions exist, where parties agree to form a coalition by negotiating a compromise between their policies.

The issue is that the US politics are made to be the same as stock market companys. Only ever think to the next term. Never think further. Never try to bring positive change over a longer time. Always just fight the next battle of existential dread and prepare the country for the next battle being even more dreadful, while the people suffer more and more.

This mindset of mainting this toxic status quo is part of the reasons, why Trump could win in 2016 in the first place. He understood that all he needs to do, is being an entertaining asshole, that claims to not be part of the establishment. And you saw, how quick some of the Reps, and many "conservatives" were to dump Trump, after the sentiment turned against him a bit after the fallout of Jan 6. /r/conservative was hilarious for this, as all of a sudden everyone was talking about how they always were wary of Trump and how it is good that the Reps would get back to being the party of reason. (With people like Ted Cruz being endorsed as reasonable, lmfao) But the Trumpists stood out the backlash and now all the Reps are sucking up to him again.

It will not become better, if Trump won't win this time, or if he ends his second term. He is only one head of a Hydra of what is wrong with the US. And the Dems are guarding the neck whenever the head is severed, so two new heads can grow.