Quit doing a victory lap hoping for Biden to fix it. He is no friend of environmentalists he is a neoliberal who is tanking his chances at relection to support a genocide.
Compromise cannidates don't work. They let the country go right with no benefit. You know which cannidate actually got lots of crossover votes from Republicans? Bernie Sanders
Sanders had the support of about 1/3 of the Democrats. You can't get somebody like that to actually be the nominee unless you get the rest of the Democrats to support their policies.
If he had a majority of Democratic primary voters behind him, that wouldn't have mattered so much. The reason he was leading was that the moderates were split across many candidates.
Vote for who you vote for. I'm in a hard blue state and I see zero reason to vote for Biden in the general. Those in swing states should vote for the democratic nominee that exists because to not do so helps Trump. In states where Biden is for sure going to win people should vote for someone else.