@Olivier5,
I don't like either of the options available to American Democrats.
If I were an American voter, I would likely* vote in the Presidential general for whichever Democrat is selected by primary voters. Downticket, I would vote for whichever individual candidate suits my preferences best. Often Democrat, occasionally Green if that made strategic sense.
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*the likely disclaimer relates to jurisdiction. In some states, it is meaningless to vote for a Democrat so I would vote for the Green candidate simply to push the number. I might still campaign / leaflet etc on behalf of a Democratic candidate but vote Green.