Mine are 1.5" different from a bad motorcycle wreck at 19. I have just been dealing with it for 50 years with no solution. I tried lifted shoes for a while but that wasn't a big help. I just limp along at my own speed.
My buddies grandpa had the same issue after hip replacement and had someone build a wedge that attached to the bottom of his shoe and allowed him to walk better without pain. Might be something to look into. Just not sure who he went to to have that built. I think a chiropractor actually recommended it to him. Good luck and hope you find a solution.
I understand that as "perfect" as nature is, "imperfections" in limb lengths are quite common. A perfectly healthy human being is probably NOT going to go through surgery just to correct an insignificant difference.....but.....it would also be just as inane that a surgeon, with the ability to correct any discrepancy in limb length, to allow any discrepancy to remain.