I like solving puzzles, and sometimes I get in a flow and it goes quite well until there is a zugzwang position... Always wrong even the 2000 or 2100 rated. My instinctive moves fail. To me that is funny. Sure, I could use more time to do the math but that is boring. To me it just means that those puzzles are for folks who like to study. But the question remains: Are those zugzwang pawn endgames harder for instinctive players?
Regarding myself part of the answer is that I only calculate attacking moves and rarely I calculate what my opponent can or will attack. A true patzer by any means. But in love with chess for almost 50 years...
I find pawn endgames fiendishly difficult, and often the only way of playing them is exact calculation which is not my forte either.
As far as general principles are concerned, I don't really get any further than the basic "opposition" in K+P vs K. Jonathan Speelman wrote a couple of brilliant endgame books, in one of which, "Endgame Preparation", he covered something called the "theory of related squares" to be applied to pawn endgames. But it was beyond me when I tried to understand it in my young days.
Brute force, no feelings whatsoever. Jussupov and Dvoretzky recommend them for calculating training.
IMHO the term "instinct" is a bit misleading and it's actually closer to what
lichess.org/@/Avetik_ChessMood/blog/analyzing-blitz-chess-games-why-and-how-to-do-it/6Nziw4Uncalls "unsconscious competence". The difference is that while "instinct" sounds like something natural, independent of your will, this "unconscious competence" (or perhaps rather "subconscious"; I sometimes call it "autopilot") can be trained and is in fact the ultimate goal of a training. Thus there is a good chance that if you focus on this kind of problems and positions, you not only get better at handling them but handling them may become part of your "instinct". Whether it feels worth the effort to you, that's a different question, though.
In my last tournament the winner(!) lost one single game (against me!) coz he played the pawn endgame by ear. You have been warned!
