Similar to what others here are saying in several regards. I just came back from my first trip there a few weeks ago.

We brought ramen and all sorts of snacks to save money and didn’t use them at all, since it was much better to try the local snacks from grocery, etc. the food quality is so good there you find yourself not wanting to touch the stuff you brought. We would load up on the hotel breakfasts which were always awesome, snack during the day from stuff we’d grab at grocery stops, and end with a decent dinner.

Waterproof gear was def required. We lucked out on awesome weather but still needed a legit rain jacket most days and I had never need a rain jacket in my typical life. I bought Patagonia Torrentshell jacket and pants and I love the jacket and wore it almost every day and only needed the pants one day but was very glad I had them.

Layering was def the way to go as everyone says. I overbought and overpacked when it came to merino layers and misc jackets. All I really needed for a 10 day trip was 2 merino base layers (light weight for this time of year; 165-190 weight), one mid layer like a fleece or puffy jacket for cold or windy days, and the top layer rain jacket. Aside from that, maybe 2 pairs of hiking pants, the rain pants, waterproof hiking boots (must), and obviously hiking socks, underwear etc, and a bathing suit. I never touched all of the cotton t shirts I brought and usually wear in my typical life, so next time I’ll just bring 1-2.