Hardening it will make it more brittle and likelier to crack (although that depends on what the temper it currently is - might ask seller or look up ASTM spec referred to from where you bought it). But, IMHO, for safety reasons it’s better that it bends than breaks from being too brittle. Like wing spars on planes - better they are slightly weaker and bend than break off.
Something that has some thick padding or hard rubber where it hits will help dissipate the shock loading. Worse case if you’re worried about bending would be to weld on the BACKSIDE of the lever with say a thick triangluar shaped flange to reinforce it and spread the load while stiffing that area.
We don’t have a hardness tester. If someone at the Space has access to one at work, could you take a small piece of the drop-off get quick test done, say on Rockwell C scale. If this number is known then the engineer types can give you better evaluations of what to do with estimated strength and the math on the localized loading. Oh - reinforce whatever it is hitting also. Gusseting the welds that will take heavy shock loads probably would be a good idea.
Considering the things the machines of death and Darwinistic things you’ve built before and personally placed you body upon - who is this new Brandon talking safety FIRST. What have you done with him!