One thing that can be important is to ensure that the MPO on the hearing aids is set fairly high. Also many times the Phonak loud noise program is far too aggressive with removing noise and can be set to activate at a higher level or turned off completely from being part of the automatic settings.
There are different targets for hearing loss such as dsl 5 which would procide more amplification in the upper mid frequencies which could improve things for you. Feedback would be a roadblock. A deep fitted mold is probably the best option if you were to try it.
Frequency shifting is good. Its best to measure the narrow band s and sh to determine if the sounds are properly separated. Also measuring the maximum audible output frequency and ensuring that it hasn’t been changed too much by the shifting. Purdue has great resources about this. Google maof maximum audible output and it should come up. Or add purdue to the search.
These are just some tools and they still might not improve things unfortunately. But there is potential for them to improve things. Anyone is free to dispute what I’ve said or give me further insights as always.