Can’t remember if I should tilt the handlebar forward or backward?

Going to guess and say forward? means your wrists/hands wont be at such an angle?

had an issue myself cured it my moving the saddle forward slightly on the rail less load on arms mor load on backside worked for me

my wrist was hurting, around the same, i brought a new seatpost and bar, i noticed one day i had the saddle right back and felt a little stretched. Changed it and no wrist problem since

Mine hurt more due to the DH bits than the uphills

Are your brake levers in line with the angle of your forearm when in normal riding position-can make hell of a difference even if they are a few degrees out.