

You’re not arguing against Democrats, you are arguing against basic math. Here is a primer for why going third party is a complete non-starter: https://www.youtube.com/watch?v=s7tWHJfhiyo
The way forward is to transform the Democratic party from the inside out. It’s not impossible, Trump did it to the entire Republican party in the span of less than a decade. Vote in PRIMARY elections.
Yes, I agree, any kind of ranked choice voting system would help to end the two-party duopoly. If you are lucky enough to have your state consider a ballot measure to introduce such a system, do everything in your power to help it pass.
Unfortunately, it will not be easy; for obvious reasons, there are many powerful political forces opposing such reform. Here is a page showing how well such measures have done in recent elections: https://ballotpedia.org/History_of_ranked-choice_voting_(RCV)_ballot_measures
By the way, if you liked the CGP Grey Animal Kingdom video, it continues as a short series: https://www.cgpgrey.com/politics-in-the-animal-kingdom/