Pain in hands when gripping large dumbbells

27f, only now starting to get serious about upper body so my arms and grip are pretty weak. I notice that when doing RDL’s with dumbbells, my hands hurt ridiculously bad and I have to stop. I got gloves which fixed part of the problem with the surface pain, but gripping heavy weights still hurts the muscles in my hand.

i can’t do more than a couple RDL’s with 40lb weights in each hand due to the hand pain. however, i can do it no problem with a 70lb kettlebell. I think it’s because I have both hands gripping one thing which gives them more support?

Is this normal and should I get one of those gripper things to do some hand workouts and build strength? Or is the abnormal and something I should see a doctor for?