Okay, so:
- Voting Democrat in the general election is the choice with (edited in: the) least horrible consequences and
- Voting Democrat in the general election isn't nearly enough to stop the ratchet-effecting into fascism, and a stand-for-nothing placeholder centrist Democrat president in 2028 will probably just lead to Trump-3/Vance/someone similarly horrible in 2032
are unfortunately both true.
Also, non-MAGA Americans - (EDIT: liberals, not the party leaders) and leftists alike - need better people skills. With infighting like this, Republicans hardly even need to lift a finger.