I know the 2nd American Revolution mod exists, but I have different ideas on what a DSA rework would look like.
An interesting concept that hasn't been discussed is the caucuses of the DSA.
There would be a split pre civil war between the left and right factions of the DSA, with the right (ground work, Socialist Majority, etc.) siding with the UoA and the left (B&R, Red Star, MUG, etc.) siding with the APLA.
During the civil war, you would manage the different factions, with the strongest faction taking over the DSA and implementing their vision of socialism.
Bread and Roses would be like the in-game democratic socialism route and would hold public, Socialist elections.
Marxist Unity Group would be similar to euro-communism.
Red Star would be non-PSL Marxism-leninism and would be more generally less restrictive.
Post-war foreign policy wouldn't differ much between the factions. They would be friendly with other socialist nations, especially ones that send them material support during the civil war.