From your posts, it sounds like you have similar boot issues that my daughter did. She has super wide ball, very narrow heel, flat but not fallen arches, pronates, pronounced achilles tendon, and her foot is very muscular and not fatty so the boot has to be shaped to her foot rather than her foot molding to the boot.
First, traditional leather soles and leather uppers only. Anything lightweight or made of plastics just didn't have enough give or wouldn't break in properly for her. Her boots are heavier because they are the traditional all leather upper and sole (layered leather and cork heel) but that seems to be the only kind of boot that works for her.
Her customs have features specifically for her feet. Lower heel height, built in pronation support, wide and rounded out toebox, narrow heel, extra c-shaped ankle padding to seat her heel, lower cut backstay to accommodate her large achilles tendon that is also heavily padded, lace bar to keep the tongue straight, and a split sponge/lambswool tongue to prevent lace bite (she ties tightly).Fine grain leather lining because she skates barefoot. She does not use any removable footbed in her skates, just skates on the hard fixed insole.
We had used good, highly regarded skate techs but they still weren't able to order a custom boot that fit. It took going to the factory and having the head tech and boot maker inspect her feet and design a boot together. They noticed things about her feet that nobody else had and came up with the above list. It took two tries, the first customs were a bit too long and a bit too wide in the heel, so we had a second pair made and they fit perfectly.
It took us five years to get boots that fit correctly and that she can wear for hours without pain. Five years of pain, frustration, slow progress and wasted lesson fees because she couldn't put in the practice time necessary. This last year of skating has been amazing and I wish we had just gone directly to a factory regardless of cost in the beginning, which would have saved money in the long run and she would be so much further along in her skating. I'm grateful she didn't give up.