This is incorrect.
Mercy’s “exploit” exists solely as a result of how jumping, crouching, and GA’s spline pathing works. It literally cannot work any other way. It isn’t tied to physics in any way, and the ability to slingshot itself which is an intended mechanic, produces the exact same height and distance as the “superjump”. It’s all tied internally to her kit, it’s not a physics bug, and there’s no way to patch it without putting an arbitrary and clunky restrictions on Guardian Angel, jumping, and/or crouching.
Doomfist’s physics bug exists because the game lacks the proper clipping for slopes, handles ledges incorrectly as a slope instead of a proper sheer cliff (likely to support Hanzo and Genji’s vault/clamber), and was supposed to have been patched and standardized when Brig’s Bash Jumps were discovered in Junkertown years ago… patching it out doesn’t make Doomfist clunky.
Likewise, Genji’s ledge glitch actually circumvented a legitimate ending portion of his Swift Strike. The ledge cancels out the momentum slow tied to the ending portion of his ability, where Swift Strike is supposed to speed you up, apply damage, then slow you down back to normal walking speed.
These are three very different coins that you’re confusing to be the same.