“Which gedolei poskim today answer pikuach nefesh shailos,”
This is the CR
We all do!
TLIK
Your inquiry is TOO simple. Some aspects of Pikuach nefesh absolutely are a specialty area.
Obviously there are general rules of thumb that every posek should be familiar with but without question many specific questions involve details that many Rabbonim are not familiar with.
Take something as routine as CPR vs a DNR. I have asked 7 different Rabbonim who have given piskei halacha on this issue. Only one was accurately able to describe CPR, its sequale, odds of success, etc.
That isnt to say this is entirly thee fault of Rabbonim
There are several reasons for this. some of the fault lies with the medical profession who are often quite reluctant to discuss details with Rabbonim, some lies due to the high stress of the situation critical information is nt given over may change the psak one way or the other