While it’s true I don’t care about some of the small paint details for I’m modifying the toy, it hasn’t been difficult for me at all to just to mask the painted areas I want to preserve and sand the rest, which is exactly what Mechapilot77 should do if he wanted to follow your own advice of sanding before matte coating anyway.
At worst, there are some areas that can be sanded and some others that can’t. Every modeller has his own techniques and I’m just saying what’s worked TO ME. And to me, it has certainly not been a “real iffy type of procedure”