Basically, yes. Speaking as someone who's voted third party before, there's no hope of changing the system by voting third party at the federal level. Game theory on first-past-the-post elections and the absolutely insane amount of money in our elections practically ensures it. The best way to effect change there is to go to some form of transferrable vote or ranked choice vote at the state and local level. There are already some states whose electoral college splits its votes in this way, and the two main parties (and their big donors) hate it because it erodes their ability to take a state's vote for granted and weakens their duopoly.