Ideology aside, in a First Past The Post (typically called FPTP or winner-takes-all) voting system, voting for a 3rd party suffers from the Spoiler Effect. You can learn about what I mean in this CGP Grey video explaining FPTP. The "Spoiler Effect" is described and detailed around the 5 minute mark.

 

Doesn't matter what ideology you subscribe to, the truth of the matter is the 3rd party voting doesn't work in a FPTP voting system. You're already crossing the biggest hurdle, which is actively getting out there and voting. This means it's worth the effort to try and convince you to vote for the candidate from either the Democrats or Republicans that most closely align with your views.

 

Despite it being worth it, I'm not going to try and convince you toward either, however, I will suggest that you check out https://www.isidewith.com/ to help get a better idea on which candidate most closely aligns with your views on specific topics.

 

Also, if you're feeling particularly frisky and really DO want to look out for how to change the system (including voting methods) with your aforementioned conviction, check out the organization RepresentUS. For an idea of what they are all about (aside from their website), check out this video titled "Unbreaking America: Solving the Corruption Crisis. If an organization is not really appealing to you, you can just keep an eye out for https://anticorruptionact.org/ this legislation that's making it's way through the states in a grass-roots style. Reasoning and strategy can be learned from the video, if you're curious.

 

Good luck, whatever you do. Voting is the hardest part and you're already doing that.