Vote for the change you want to see.
The Republican party got remade because trumpists showed up and outvoted the party elites. No reason it can’t happen for the Left except for laziness and apathy.
If all the progressives furious about the state of affairs now had shown up for Sanders in 2016, I doubt we’d be in this hellish timeline. Sadly, he needed the young progressive vote to show up.
You’re allowed to do whatever you want.
If you want to actually make a difference you use strategy.
The smart play is to get a Left leaning Dem nominated. Most voters aren’t going to vote for a 3rd Party candidate no matter how good they are.
I’d rather vote for a mild Left candidate who has a real chance of winning than throw my vote away on my ideal candidate.