Honestly, the best bars and stem height/length depend primarily on how one wants to position themselves when riding. Upright, forward leaning, aero (or recumbent). Then finding the right angle(s) and grip get addressed. For road bikes that's why I see so many raised stems on drop bars.

if not obvious, find the right saddle and position of comfort for back, arms, wrists, hands, before picking bars.
Heck you haven't even said what type of bike it is. Or the stem being used.


Personally, @ 73 - on a road ride of more than a couple of miles, there is no one position of comfort for my hands (or other parts). I have to move mine around and change the angles. Which also helps keep me from over-gripping. So I ride drops. Shorter stem on some maybe, short and shallow bars on some, shorter cranks too, during some overhauls. But I always move my hands throughout every ride, leading to different back, shoulder, arm angles. So everything moves and adapts to the stresses within a certain (limited by fit) range of motion. If I come home tired, hopefully it is that tired-all-over feeling. Same with saddles = gosh do I move around and ride light and get out of the saddle even on relatively flat rides. Doesn't everybody do that on the road? Mountain bikers sure move around a huuuge amount on their machines!