MLE, I quite understand your position, I am in similar "shoes"
fading as an elder is virtually impossible without facing more or less serious questioning.
If its not health, it must be something else. In my case, we had an elder resign some years ago, apparatently due to secular work reasons.
However, some time later, the real reason came up, he cheated on his wife.
If I ever would resign, I´m sure suspicions in this regard may run high, because my health has been very good so far, and I´m not good at faking things.
My goal is to resign sooner or later, but I need to find the appropriate timing. I work on my wife to get her used to the idea of switching congo, because this may be my only change.
But right now, we have a small BOE, where each one is needed desperately. Fortunetely, my fellow elders are of the more reasonable, intelligent kind, company men yes, but as open possible. My little influence can help to take advantage of that, and I could at least once prevent an unnecessary JC, by avoiding the merely legal aproach on things.
There is good that can be accomplished by those of the "conscious class", before they fade or drop out.
Maybe thats something in the end, that helps deal with the responsibility before God, however we may define it.