Man, i feel that anxiety in my soul. I had a cheap plastic leg lock give out on me a few years back and almost lost my whole rig... scariest second of my life lol. Since you're rocking that heavy D850 setup, you definitely need something way beefier than those entry level kits. Honestly, you want something that prioritizes stability over being super lightweight if you're gonna be in windy spots. I've been using the Benro Mach3 2 Series Carbon Fiber Tripod TMA28C for a while now and i'm super happy with how it's held up. It's basically a tank. The carbon fiber is great for those PNW trips because it doesn't get ice cold to the touch like aluminum does, and it actually dampens vibrations much better when the wind starts kicking up. I've taken mine through mud and sand and the twist locks are still smooth as butter. For the head, dont skimp on the ball diameter. That slipping you're dealing with happens when the ball is too small for the torque of a heavy lens like the 24-70mm. I'd highly suggest the Benro B3 Triple Action Ball Head. It works so well because it has a huge load capacity, so you wont have to crank it down till your fingers hurt just to keep the camera level. This combo should stay right around your budget and it'll give you your confidence back before your trip.

Like someone mentioned, stability is priority one. In my experience, these offer the best value for heavy rigs:

• Leofoto LS-364C Ranger Carbon Fiber Tripod
• Sirui R-3213X Carbon Fiber Tripod

Just saw this thread and honestly, you're right to be worried... that Nikon D850 is a tank. Over the years, I've tried many different setups and seen way too many people make the mistake of trusting those travel tripods that claim to hold 30 pounds but then start vibrating the second a light breeze hits. In my experience, those manufacturer load ratings are basically fiction. If you want something that won't give you heart palpitations, you really need to look at the leg diameter first. For your specific rig, you shouldn't go below a 28mm top leg section... anything thinner is gonna flex way too much under the weight of that heavy glass. One big thing to avoid is using the center column extended. It basically turns your expensive camera into a pendulum. Tbh, if you can find a set of legs that doesn't even have a center column, or at least one that allows you to swap it for a flat plate, that's gonna be way more stable for those long exposures in the PNW. You don't need to spend two grand on a boutique brand, but trying to save fifty bucks on a budget model is exactly how cameras end up in the mud. Also, be super wary of tripod heads with small, plastic-feeling knobs. When your hands are cold or wet, you wont be able to torque them enough to keep that heavy DSLR from sagging. I always tell people to check if the ball head has a separate friction or tension control... it prevents the whole thing from flopping over and smashing your fingers if you accidentally loosen the main lock. It's a safety thing as much as a stability thing.

Saved for later, ty!