I wear hearing aids. More on that in a bit.
I agree with Steve N. about improving the source. I've been refining my system for years, but it was a game changer when I started into Auralic and moving up their line. I'm a bit embarrassed as to what my streamer/DAC with external master clock cost, but now that the money is spent, I have no regrets whatsoever. Everything improved but, most importantly, sound smoothed out while detail increased and the sound floor lowered. Here's the porn: . . . . . . . . . .
I've been fortunate to have both a First Watt J2 and the Inspire pre and amp you see in the photo (red). I just sold the J2. It would do what you say you want, extend the freq range upward, but it did have ever so slight edge when compared to the tube setup. I think smoothing and extending in other ways would be preferable. And there is that magic tube midrange when you've got the right amp set and right tubes for your ears. This may be due to my hearing and interaction with the aids since no one else seems to have that opinion about Pass designs.
At the other end of the chain from the source, consider supertweeters that roll off from about 15kHz. If you power them with a separate amp, you can dial in the best blended level to complement the Omegas. I have an older thread here about my supertweeter project. I'm not using them currently.
Also with regard to speakers, Louis' ferrite drivers will have stronger/brighter highs than the alnicos. I would never give up the glorious texture and depth of the alnicos though.
I bet my hearing loss is worse than yours or you would have aids already. I started wearing them in the early 2000's and they have come a long, long way. The current crop is aware of the demand for better music listening and will often have a music program (most have several programs like "automatic/general", restaurant, music, etc). Alternatively, your audi can create a program for music by turning off as much of the digital processing as possible (compression, noise reduction, and the like). This renders the music to have more natural sound than the harsher, speech oriented regular programs. I adjust the volume in my music program to just supplement sound a bit and I get better high frequency experience.
If you have any trouble hearing people talking either in a quiet place and/or a noisy place, aids will amaze you. You'll feel less tired after events or work, if you communicate verbally there. You can stream your phone to the aids. Some have bluetooth built in for direct streaming (mostly iPhone) or via a disc you wear around your neck - under your shirt. I can hear phone calls better now than I ever have! I also have a small, remote, bluetooth microphone that others can clip on so that streams into my aids as well. My work involves talking and listening. Without the mic, I would probably be unable to do my profession adequately. I use it only for about 15% of my clients now, but that is increasing as time goes on.
I buy mine a Costco and am fortunate that the dispenser there is very knowledgeable. A pair of good ones there will cost about $1800-$2200. They are about six months behind in what they carry, no big deal for me. The same aids from a private audiologists will cost more than twice that.
Here's a link to the best hearing aid forum I've found: https://forum.hearingtracker.com/
. They have reviews of various models and lots of experience there.
Anyway, that's probably about $.06. . . . . . .....Peter
BTW, Louis let me know my SAMHO's should ship this week. They will be replacing the regular SAMS I've had.