I've spent a lot of time lugging gear through national parks over the years, and honestly, the stress about having the widest possible lens is something every beginner goes through. I've tried many different setups, and for a place like Glacier where you’re hiking a ton, reliability and weather sealing matter just as much as focal length. Since you're on a $500 budget, here is what I would look at to keep your shots crisp and your gear safe:

• Nikon NIKKOR Z 24-70mm f/4 S used. This is my top recommendation for a conservative buyer. People call it a kit lens because it bundled with the Z6, but it’s part of the S-line, meaning professional-grade optics. I've found the weather sealing to be incredibly reliable when the mountain weather turns sour. You can find these used for $350-$450 easily. It's way more versatile than a prime for your first trip.
• Nikon NIKKOR Z 28mm f/2.8. If you want to keep things light, this is a great little prime. It’s tiny, sharp enough for big prints, and very affordable. 28mm is a very safe focal length—wide enough for the peaks but without that crazy distortion you get at 14mm.
• Viltrox AF 20mm f/2.8 Z. If you are absolutely dead set on getting those ultra-wide shots, this third-party option is surprisingly decent for the price. It’s budget-friendly, tho it lacks the robust build quality of the Nikon S-line stuff. In my experience, grabbing that 24-70mm f/4 S used is the smartest move. It covers almost everything you'll see at Glacier. If a mountain feels too big, just shoot a vertical panorama and stitch it later.

Building on the earlier suggestion, I have to be real... unfortunately, that 500 dollar budget is gonna be super tight for native Z glass. I had issues with the standard 24-70mm zoom because 24mm just isnt wide enough for those massive valleys. It felt pretty cramped for my taste. Quick question tho, are you planning on doing any astrophotography or just daytime hiking shots? If you want decent results on a budget:

• Get a used Nikon FTZ II Mount Adapter. It opens up way better deals.
• Look for a used Nikon AF-S NIKKOR 18-35mm f/3.5-4.5G ED. Its not as fancy as the S-line stuff, but fits your budget.
• I tried the Nikon NIKKOR Z 28mm f/2.8 but the edges were not as good as expected for fine mountain details. Using the adapter is slightly clunky, but it is basically the only way to get wide vistas without overspending.

Honestly, you are gonna have an amazing time at Glacier! That park is basically a cheat code for landscape photography because everywhere you look is just stunning. I totally get the stress about glass though. Tbh, Nikon has some of the absolute best optics in the game right now for their mirrorless system, so you really cant go wrong staying within the brand ecosystem. If you are just starting out, dont feel like you need that super expensive gold standard stuff yet. I spent years shooting with basic wide-angle zooms from Nikon and the results were always fantastic. The sharpness you get from their modern lens designs is just incredible, even on the more affordable stuff. My advice? Just get any Nikon wide-angle zoom you can find in your price range. Having that flexibility to zoom in and out while youre standing on a ridge is a total game changer compared to being stuck with one fixed view. You really want something that lets you capture the scale of those mountains, and Nikon glass is famous for how it handles that crisp mountain light. Just trust their engineering! Grab a versatile Nikon zoom and focus on the composition. Seriously, the gear matters less than being there at sunrise. Youll get those sharp edges and beautiful colors regardless of which specific Nikon zoom you pick up as long as it fits your budget! The Nikon Z5 is a beast and it will handle any native glass you throw at it perfectly.