Deathless as the base category was meant for a run off this game without deaths while playing through the game normally. However a new run has been done following basically the any% route just changed up to not cause deaths (an impressive feat to be sure). Due to the fundamental difference in strats, i don't believe it should be placed in the deathless category. However does this deserve to be placed in the any% or a new like "glitched deathless" category.
The spirit of the "Deathless" category seems more like "No Major Glitches". Even the rules today for deathless mention both death warps and wrong warps being prohibited. If it were called NMG, it would seem more straightforward to just add a newly discovered major glitch to the rules.
I'm not sure if you'd call the creative grapples in the run above wrong warps or something else, but they definitely feel like a major glitch.
I feel like there is no need for a Deathless Glitched category. The whole point of the Deathless category is to go through the game normally without dying, using wrong warps goes against the spirit of the category, so a Deathless Glitched category seems unnecessary. While the route is interesting, to me it is just a slower Any% route.