I'm 10 or so hours in and have stolen high tech from a corporation (cool), resurrected a dead terrorist (possibly cool, still don't know his motivations), and drive-by-hacked various cops' cyberware while travelling the city (funny).
Outside of that, the side content seems to be entirely social services oriented. Batman the cyberpsychos. Judge Dredd the crimes in progress. Ambulance a guy to a doctor. Social Worker a cop having a mental breakdown. Chat to various people. Is there some sort of "do cool crimes" set of side content that I've missed, or did CDPR just make another sheriff sim?
I got that they were big on personal modification, but reading their lore entry off the wiki I'm now realising CDPR actually expect you to read through all the lore entries instead of being shown through the story. Now I gotta check if the mox are actually the queer/sex worker gang like I think.
In the case of Maelstrom I actually got their neo-nazi origins from the Cyberpunk Red sourcebook, which details how Maelstrom formed from the union of a neo-nazi gang and a "cyberpsycho" extremist gang. I don't know of anything in-game more detailed than just their general sadism and might-makes-right fascist behavior.
I feel like they're kind of underdeveloped in the story and mostly pop up in the background, probably because someone realized making them another faction like the other gangs or the corpo security groups would mean gamers could hunt them for sport and that would be terrible optics. Otherwise yeah, they're basically a militant sex worker union that responds in kind to the casual cruelty and violence sex workers face.