Andy,
I wouldn’t get caught up thinking it’s about the hardware, until you have exhausted all the programming options for the hearing aids you already own. In my opinion almost any of the major brand hearing aids over the last 10 years should be satisfy your music requirements if properly set up.
This is where doing your own programming can be very satisfying. Just as long as you save your program settings, you can always revert to a previous program and start over. No mistakes are permanent, you can’t screw it up. Actually it can be fun to try different things to see what works best for you, and there is minimal initial cost.
I play some classical guitar and mandolin, and am totally happy with the dedicated music program I set up. I didn’t get it right the 1st time, but after a number of improvements it’s working great now.
Give DIY a chance, and save yourself a ton of time and money.