I think “slur” also requires a component of direct offense for it mean anything. I don’t think it is valid to be offended for somebody else if that somebody else isn’t actually offended. If I make up a slur on the spot denigrating some aspect of your person that you do not find offensive (eg. Flumplenook - for a person who’s a bit clumsy), is it really a slur?
So if you call someone retarded, and they do not have the mental faculties to be offended, is it really a slur?
For slurs to have any meaning, any power, they need to be understood and internalized as offensive.
Nothing but empathy for you here, bro. Try some drugs. Not the shrink drugs, but some psychedelics. There is some inherent risk with HPPD, but you’re already wanting to opt-out of life, so that could be acceptable. Read up on set and setting, do the prep, find someone experienced that will trip sit. And be prepared to feel overwhelmed, possibly from profound thoughts, and for some very honest introspection and soul searching. Totally okay to sob your heart out. Psychedelics are not a panacea, but they can be a tool to help you out of the local minimum.