Death grip isn’t grabbing the bars too hard, it’s holding the bars not the brakes which has to 2 effects, reduces arm pump as the muscles/tendons in your forearms aren’t stressed anymore. And makes you faster by reducing the tendancy to subconsciously tap the brakes every so often to give you the sense of control. Hence death grip = fast.
1 finger braking is good as it reduces arm pump, most people use their index finger, some use their middle finger. Some disagree with it entirely for some reason, but I can’t see any disadvantages to it with modern disk brakes being so powerful (even on well set up V’s or weak XC disks it’s more than enough).
Setting the bite point to as close to the bars as possible has the same effect on reducing the tension in your forearm muscles and reducing arm-pump. I run mine so in a car park test I’m convinced they’re not going to work and the levers reach the bars with little effort, but as soon as there’s loose surfaces thrown into the mix they lock up well before they hit the bars. Makes braking the same strain on your arms as just holding the grips.
Try it, you’ve nothing to lose:
*death grip (properly off the brakes, not grabbing the bars tightly)
*1 finger braking
*bite point right against the bar
That and there’s just general riding technique, I broke my arm before christmas, 3 months later my arm was too weak to even lift stuff (it still struggles to lift a bike over a stile and I can’t press-up properly) so I’ve re-learnt how to ride doing a lot more through my legs and gradually working my way back over the front of the bike as the strength comes back. So it is possible to ride quickly with different technique, just look at some world cup DH video’s there’s not one technique, they all do things differently (or copy their mentor cf. Brenden looks like Peaty, Brosnan looks like Hill, etc)