Ear wax check and removal once a year is covered by health care, as well as controlling the hearing aids.
I'm skeptical about cleaning my ear tubes in the shower, as contact of the ear drum with water is not recommended, ear way does not dissolve in water, and the same goes for cleaning agents of any kind. Mineral oil cannot be absorbed by the human body and I will let none of this contact any part of my body. (Vaseline would be the exception only if protecting the skin from anything after any damage would be advised.
Cleaning the hearing aids is another question. I try to do it, but is tricky and requires much care or you damage the intricate tiny electronic parts.
Nothing like the real thing .....
Thankd for posting the links about dementia. As I understand it, it is the restricted stimulation by reduced social contact and aural information, kind of a deprivation, that enhances demtial processes. Whether hearing aids can remedy that, is another question. But they are helpful, I would be the last to deny that. I use mine based on the situation.