With your hearing loss, I would think the KS8’s should work quite well for you. They work really well for my right ear which has less loss, but more than yours at higher frequencies. I am struggling with feedback in the left ear which needs more gain. Next step for me is to try an earmold.
Some things you should ask Costco to give you to try is both an open sleeve fitting, as well as a closed sleeve. Also make sure they do the Own Voice training and turn it on. I helps especially with a closed sleeve. A closed sleeve should give you a bit more directional control of the microphones.
I find the directional microphone control with the app works quite well when you adjust it down to a narrow front beam.
The Noise/Party program is the one I find best and use in the gym during a workout.
The iFocus 360 seems to work really well in a car/truck on the highway.
The listening to music program seems to help with the music quality issue.
I’m not real impressed with the wind noise reduction in the Outdoor/Traffic program, but I have never had any other ha’s to compare it to.
Some Costco’s don’t turn the optional programs on, or do the Own Voice unless you ask them.