Is the best way to push Biden in a less corporatist & more humanitarian direction to stay within the Democratic Party in exchange for perceived (or imaginary) access, or to form another party that could actually threaten the citadels? Not saying I know the answer; I’m just asking

History favors the first option, the second has usually failed. Except on the Republican side where upstart parties occasionally have reordered the major one. Like you, not saying this is the answer; I'm just replying.