Sorry to read of your health, I think this is something we all have to face and you are right, leaving it to a spouse or partner puts a greater burden on them. I bought pieces from a friend’s estate after he passed, in part to help out his widow.
Maximizing return, for the sake of your estate, would require far more effort than "one stop" deals, like working with TMR or Sky-Fi. I also have Avantgardes (Duos) and they are a bargain today used, compared to the current new market prices.
Same with records, you can either try to maximize which involves more effort (or finding someone like I did, who was willing to take unwanted LPs (about 12 thousand at the time, leaving me with around 5k LPs)), removing them from my place, listing them, selling, shipping, and sending me 50% of the net.
Yes, any dealer is going to give you far less than market, but the one key thing is to get them to take all of it (if that is what you want).
Other alternatives, with physical media and possibly gear- donate to a music school or library if they have the facilities to actually support such a gift.
I appreciate that part of this is peace of mind and not introducing more stress into your life.
I wish you the best,