Oh man, I've been there! For bright days I actually really like Ilford HP5 pushed to 800. It keeps the grain nice and chunky but handles the highlights way better than Tri-X did for me in that situation. It gives you that texture without just turning into a solid black and white mess. Have you tried pulling film a stop instead? That can help a ton with contrast in harsh light.

Okay, "weird little metal box" just makes me think of those escape room puzzle kits people buy as gag gifts. Someone probably got it for their birthday, thought it was dumb, and chucked it. The key opens a locker at a bus station that closed down three years ago, and the paper is just the locker number. The most boring story is that it's literal trash from a failed prank.