Without perks but maybe at least Gorilla Arms, you have to counter everything and just keep wailing. The twins definitely did not prep V for other fights as they are significantly harder.
Comes down to a few things
- Boss-like HP and resistances
- Level difference
- Your level and perks
- Your gear (cyberware specifically but also mods on clothing)
- Your ability to successfully counter, dodge, and land hits
The Street Brawler perks definitely would make it easier but I was on the same boat. I started doing more and more damage once my level went up (i.e. Threat Level went from Very High to High, to Moderate, etc.). It gets easier, but the challenge is will always be there if you don't spec for it. It's definitely doable without perks.
Now I'm just stuck on Rancho Coronado...that's...yeah.
It could be best to save before the fight to get a feel if you can inch your way through the fight and just reload if you aren't ready. Comeback later