Don't need to hear above 12khz ..and you don't even need to mess with 12khz unless you're trying to make a boring singer sound airy.

I'm not claiming to be super human or anything, from your diagram it now makes sense to me, I've seen mastering engineers boost 24kHz quite a few times to increase the air in tracks, just sayin.

I don’t know the actual numbers but I haven’t been able to hear hi hats in my right ear since 2013. Anything panned to the right is uncomfortable and slightly muffled. Anything panned hard right actually makes me irritable. Playing headphones too loud in my 20s really messed me up. I don’t remember if it was gradual or one loud bang in my right ear, I just woke up one day and it was gone. For a little while I thought it was my right studio monitor going bad. Sucks.

Believe it or not I am actually getting better at mixing..my brain somehow fills in the gaps..I’m 32 now but hopefully I won’t go deaf before I’m at least 40.

I'm going to chime in here as I've been really struggling the last few months to make sense of and, adjust to, some significant top end loss / muffled-ringing in R ear.
It's been recently accompanined with dizziness / vertigo. I've seen an ENT a few years ago. Though it then resolved itself but, it's never been this bad since it returned.
The feeling of blocked / high end loss has stopped me from being able to really get studio work done recently, not to mention the non-enjoyment factor when I try and, inevitable depression that can ensue until one "tries" to adjust ones attitude.

Saw a specialist last week that did more Audiology tests and ordered a **** load of workup (MRI, CT, blood work, balancing tests etc) Basically a drop at 4-6k in the R ear reflected on tests. Funny, I actually predicted the exact region before they told be.

Anyway, I want to mention this for any Philly region folks ...that Dr Lyons / Satiloff & Dr Unsal are specialist in the city (drexel group) that focus on musician-singers / engineer / producer type folks. They're said to be really good at this stuff fwiw. Soon to see but, they're certainly have an interest in us types, are thorough & caring.

Bottom line is we all have to adjust our perspectives when these things creep up & slap us around. Tough to be sure for folks that so highly value sounds & listening.
But, hopefully I, and others trying to tough through, it will find a place in which we can still have the abilities and,
sense of purpose to get some above average tracks finished, enjoy it & keep movin on.