I feel like you are trying to do some complex strategy instead of doing something simple The only hard thing in that fight is that you have to be aware of 2 targets at the same time, which with controller (at least for me) is hard. Maybe CDPR should consider adding some extra UI elements like a minimap (as V should have greater senses than the player) as an option. But anyway about the fights - I haven't done the fight in some time, so I may be wrong, but learn to dodge. The second 'twin' has a predictable attack pattern and as the easy fight, they were very easy to stun. Do you have points in the tree? To make blocking easier (also an idea if you get good at counterstrike/blocking at the right moment that will pretty much win the fights for you), to get (Up to 5%) hp on punch etc?
I completely disable dodge because I almost never want to use it in the game normally but because many functions are all on one key on the keyboard (ALT) it is easy to accidentally trigger dodge and go flying off a roof or break out of stealth and alert enemies. I just dodge by moving my feet in the direction to get away and/or jumping regular or with the double jump boots.
In my 2nd playthrough I saved the Beat on the Brat until the very end, and I maxed out Street Brawler and several other skills first, and then went to do the fights. I beat the Twins, Buck, and the Valentino one by using scanner slow-mo and jumping behind their head, toggling off scan long enough to punch them once hard, then turning it back on and double jumping again. The 4th fight I didn't have to do because the game spontaneously granted me completion of the 4th fight in the middle of a completely unrelated quest as a pleasant game bug in my favour.
I spent many days beating up Valentinos and 6th streeters in alleyways with gorilla arms and developing some fighting skills that just use standard movement and punch to the point I got really good with it and could be aggressive and confident and Rambo right into crowds of them and beat them all up no problem. Once I maxed out Street Brawl and some other skills and assigned all the perk points I got, I eventually got to heading to Pacifica for the final fights. I used health/stamina boosters plus food/drink booster and fought Ozob without using slow-mo and just pounded the heck out of him old fashioned style, he never even touched me. That boosted my confidence for the final fight against Razor.
Got in the ring with Razor and aggressively dove at him right from the start and let loose and got him down to about 25% health in about 5 seconds, then avoided him a bit then he one shotted me. I fought him about 15 more times and was never able to repeat my beginner's luck of the first match, perhaps my confidence dropped after I lost or something I dunno.
But, after much frustration I found a way to beat Razor using brains over brawn. I just fought him by blocking and doing nothing else. My blocks blocked almost all of his attacks, but then when one of his punches did get through he dropped my health down to about 20% or so which triggered some cyberware I have to blast him with an electric shock which did mega damage to him while healing the damage he just did to me. Then I just hit block and held it again and kept him in the center of the screen until he did it again. The second time he broke through my block the electric shock he got wiped him out but his attack only took me down to 20% health again so it was a pretty exciting win to beat him brains over fists. I was pretty stoked. Hehehe.
I forget which cyberware I have that does that but it is one that gives you a booster shot of health when someone dips your health below 25% or something like that while zapping them with electricity. It's so powerful it dismembers lesser enemies when it triggers, pretty cool. One blast of it took more than 50% of his health easy. So if anyone has trouble beating Razor this is my recommended way to defeat him. You do however have to have enough health and armor to be able to survive one of his punches without getting one-shotted for it to work though. My health going into the ring was 1088 including boosters IIRC.