HOTAS Cougar Paint Care

My own Cougar throttle. Notice the area of wear.
In the centre of that area I first applied a couple of strokes of clear nail varnish.
I could have used black varnish, but the intention was to see whether the edges of the exposed paint were protected - they were!
As expected, the nail varnish has prevented any further moisture damage to the painted surface. The main concern I did have was of an adverse reaction with the paint. There was none after 3 weeks of hard use .
Now I can proceed to coat the area of most wear - where the palm of the hand rests on the throttle.
Paint degradation on a flesh to painted metal interface will inevitably occur - it's just a question of when
The only ways I know of to prevent this in manufacture are by using baked enamel coatings, which is a more expensive process. Note that it apparently even military controllers are only spray painted. (Also note that I am not an expert in industrial finishing.)

HOTAS Cougar: Paint: definitions

From The Coatings Guide:
Paint: conditions of use
" When we remember that the average paint coating is only about two thousandths of an inch in thickness and we consider, at the same time, the number of different factors on which its durability depends, we may well wonder, not that failures and defects sometimes occur, but that they do not take place far more frequently.
Certain defects in painting work are inevitable - that is to say, they are due to circumstances which could not have been anticipated and against which it would not have been reasonable to take special precautions.
Rain or fog may suddenly occur... painted metalwork may be exposed to an abnormally high temperature... conditions such as these will impose a greater strain on paint, no matter how good or how carefully applied the latter may have been, than it can bear, and it would be unreasonable to blame anyone for the breakdown.

HOTAS Cougar: Paint and moisture

Outside moisture... can penetrate a paint coat and result in cracking, peeling, discoloration and premature paint failure.
Dark colors which absorb heat and thick paint coats are more likely to blister than white paints or thin coats.
Elimination of the moisture problem is the only practical way to prevent moisture blisters in paint. The moisture source should be identified and eliminated.
If blistering does occur... scrape off the blisters, smooth the edges with sandpaper and spot paint the area.
Baked-on enamel surfaces such as used on automobile exteriors are the most durable.
Metal having had a metal primer applied first to a spotless, grease free surface, and dried, with a second coat of paint or enamel is next in durability.
Paint or enamel applied directly to a metal surface is least durable, and more subject to bubbling, peeling and chipping than either of the above methods.
From Michigan State University Extension
If you are really worried about this effect I advise:

HOTAS Cougar: Paint care 2: Preparation

Use tissue paper in a light rubbing motion to remove blemishes and damp areas.

I never finished this article. A cursory glance at pictures of real military equipment wll show that paint wear is not considered a problem. And we are going for authenticity here, yes? - MiGMan

HygroscopicDescribes a substance that has the property of readily absorbing moisture from the air.
Peeling Failure of a coating film to maintain adhesion with its substrate. Sheets or ribbons of the film detach from the substrate. The condition results from contaminated surfaces or excessive differences in polarity and thermal expansion characteristics between the surface and the film.
Humidity resistance Ability of a coating and the substrate it is protecting to resist damage or degradation due to changes in humidity