The main factions are:
a local soviet council with soc-demmy tendencies reflecting the Soviets' canonically cooled-off relations with the US
Remnants of the Chinese government attempting to reunify an alienated eastern bloc before NATO can get back on its feet
A Makhno-esque black army that demands autonomy for the local people
The main driver of the conflict is control over a robotics factory that can be salvaged and converted into creating power armor
Later on you find out that the Enclave is stoking the fight by releasing capitalist super mutants, and the final climactic battle is set against a backdrop of a kaiju fight between Liberty Prime and a giant mechanized The Motherland Calls
They all should
You can if you want but I'm too lazy to actually do anything about this, I just thought it would be a cool idea. Anyone is free to do whatever with it as long as it's good and there are a lot of explosions during the end fight
Here me out you should be able to side with the enclave, but they should get you to do a bunch of messed up shit