The answer is not to embrace Republicans. The answer is to burn the Democratic Party to ashes. They need to go the way of the Whigs. They're simply irredeemable at this point.

If that's not possible, honestly I think progressives would have better luck running as Republicans than Democrats. Republicans don't really have an ideology anymore. They're all just celebrity, vibes, and raw emotion. Maybe progressives should start running as "radical Republicans," declaring that their intention is to resurrect the spirit of the post-Civil War party. That honestly is probably the quickest way we have now of actually getting progressives elected.

One thing about the Republican party is that it's much more vulnerable to outside disruption and takeover. Trump proved that. The Democratic party meanwhile goes to great lengths in its organization and primary structure to prevent outside usurpers from coming in and grabbing the nomination in a big populist wave.