Honestly once you sort of realize that you can’t be on the left and also support authoritarianism/fascism (regardless of the label or intent) the factionalism kind of isn’t as troublesome or confusing.
You end up with those who believe in supporting progress informed by rational, current understanding of reality and then you have those who cling to failed ideas the same way conservatives do.
The left can debate solutions and data reasonably without splitting into contradicting camps, people just need to always check and see if they’re actually oriented towards the defining principles of left wing politics; bolstering human rights and well being, strengthening democratic institutions and outcomes using the most current understanding of the world we have available to us right now.
The left, by definition, flexes and adapts to reality to achieve an outcome, conservativism is when people try to bend reality to fit their ideology.