I used to want a lot of things the Dems promised, had a majority for, and then did nothing about.

This is effectively untrue. Sure, there were a couple of times where there were more people with Ds in front of their names in both houses, but the reality is (and any genuine objective person who pays attention knows this) it's been razor thin, and there have always been a couple of "moderates" who oppose these things (2 of whom have even left the party, showing how much they were even part of it to begin with) and thus making it impossible to pass. Throw in stupid shit like the filibuster and it's no wonder democrats can't get sweeping legislation through.

If you want these things, and you're instead voting third party, you're acting against your best interests and simply casting a vanity vote. That's your choice, but don't pretend that you actually are working for change.