The Costco Hearing Aids are refundable for months and cost around $1300. They aren’t perfect for music even with the HiFi setting . Upper frequencies get screechy. I can’t practice the piano wearing them and I choose not to use them while listening to my good system, although I leave them on for the third system which is mainly for video and background Internet Radio . Where they really help is for speech recognition and ambient clues. I have used them more for streaming lately-they aren’t as good as even Apple AirPods-but they did get noticeably better after an update last summer.
You can’t lose financially with Costco, given the much lower price and the return policy. My recommendation is try them. Would 6K buds be better for music? My audiologist at the University of Chicago says no, but then most people don’t think that an expensive audio component is worth purchasing when cheaper alternatives exist. I haven’t sampled the higher priced buds and I don’t know how to go about doing that.