Honestly I might favor Conor. His cardio was never as good as Volks nor was his wrestling or grappling but I think his defensive wrestling would have probably been good enough to keep the fight mostly upright vs Volk. Volks chin has never struck me as great and he really seemed to have trouble with Islam's length, timing, counters and being a southpaw. Conor was also a southpaw, quicker, hit harder and the his ability to time and counter was always quite good.
I think we forget but Conors run at 145lbs was amazing through Holloway, Poirier, Mendes and Aldo...Absolutely a generational talent, I think he was always a little small and lacked the physicality for 155lbs no matter how much he tried to build muscle, 145lbs was Conors best division.