I voted third party in 2016 every chance I had. Then I voted 50/50 between Democrats and Republicans where that was the only choice. In 2018 I didn't vote for any Democrats.
I voted third party in 2012 too, though I was a delegate for Ron Paul. Once he was out of the running I voted Libertarian.
The system is rigged heavily even at the local levels against third parties. The only way those ideas currently have a chance is to infiltrate the two parties.
For clarity. I did vote for Obama in 2008. Then he proceeded to do exactly the opposite of what he campaigned on for every single issue I voted for him on.