this question is kind of backwards because it presumes the DSA isn't exactly where it always intended itself to be. it's history is - from the start - deeply socdem and it's always seen as its highest calling the capture or defeat of the democratic party. that means it's core purpose is and pretty much always will be to recuperate a leftist movement and shephard it back towards the realm of bourgeois politics.

but if we assume that the org might have been something else, political education would be critical. the org today is rife with people using social justice or communist rhetoric in reactionary ways and people generally don't know how to discern those kinds of bad faith arguments which leads to a lot of abusive people being given political power on the basis of their confidence.

but generally, the thing you're fighting is the iron law of institutions: as an organization grows, people with power in that institution will work towards the accumulation of their own power, even at the expense of the organization itself.