Not a pilot but I'm a 'radio nut', I've also found my fat fingers press the wrong buttons all too often
My solution is to glue a shirt button or a small 'anything I've got that fits' onto the one I need most which raises it above the ones I don't want to be pushing. You can use something smaller to, just don't make it so big that you can't press the surrounding buttons without pressing the modified one. This also creates a 'tactile' button so you can feel what you're doing as well as seeing. And if you've got a button you don't want pushed, find something to make a plastic ring to fit around it. You can still press that one, but you will have to be centered on it- 'tactile' assistance again. If you can get by with a smaller 'tactile' button, just a blob of glue alone might serve your purposes well. My radio stuff has every variation of this theme. Looks odd but works fantastically and it's performance that I'm seeking.
Not wanting to 'goo up' any expensive equipment permanently, I test the glues with a tiny dab on an inconspicuous part of the plastic to make sure I'm not going to permanently disfigure it- many glues will 'melt' different plastics. So far the glue I've found that works best with most plastics is "Shoe Goo", well known in the US to hikers and campers. Holds very well, but can be peeled off when you want that. "Household glues" are similar but more viscuous which can be a problem. "Hot melt" glues work with other plastics, but don't let them get fully hot before use, just enough to barely melt the glue to start with- you'll have to experiment here. Sometimes rubber cement or tire patch glue works well. Stay away from 'strong' glues like those for plumbing pipes and super-glues, as they may actually destroy the button underneath or become permanent. Also avoid brittle glues like epoxies and wood glues as these sometimes pop off all too easily with flexible plastics or in the heat of sunlight. Always test function well before putting the modified unit into service.
With the right stuff, the button enhancements stay put under all conditions but the shoe-goo seems to need renewing every year or so which is easily done. The best part is that you can usually peel the button and glue off carefully anytime you want with no harm to the buttons save for paint markings. You just make sure that no glue goes where the paint is and even that comes off clean- but only when you want it to. Being that there are so many plastics that react differently to different glues, you're on your own if you try this. I'm just passing along my solution to to similar problems that has worked excellently for me.