Something I feel would be a useful tool, but one with tradeoffs and opportunities for additional immersion is something like a "spyglass", or a typical handheld monocular or telescope. We can already "zoom" in by reducing our FOV, and there are even "Zoom" mods that allow for this to be toggled on and off with a button press. Yet I'm not a robot with zoom lenses.
The situations I find myself wanting a spyglass are:
Hunting. I want to better understand how to approach a goat, boar, moose, goat, deer, etc. Where exactly is it, what's around it, what my approach should be.
Exploring. Can I see further into that cave without having to first traipse inside? Can I confirm I see something exposed of interest high up on a cliff face? Can I get a closer look into a diverging valley to make a better decision as to which direction to take? Is that really "Land Ho!?" Do I want to land on that shore, or continue past?
I don't feel this should be something you use "passively." It should be something you actively use. You're potentially letting your guard down as you eliminate all of your peripheral vision to see something far out into the distance. It should be quick and easy when in in action slot (or perhaps off-hand), but this shouldn't be like adding a "scope" to your bow where it feels like a free and obvious advantage you want to use at all possible times. The intention is you're trading materials, an inventory/action slot, and some ability to be "at the ready" in combat in exchange for saving time by being able to make better informed decisions by having better information in a way that can still be immersive.
Spyglasses were meant to be used outdoors (especially in sailing), so anything that could oxidize (copper, iron) wasn't considered. Typical spyglasses were made of brass or bronze. Moreover, these were precision instruments for their time. As a result, I figure crafting one shouldn't be trivial. Obviously it needs to use a form of bronze for the enclosure, but I would think it'd need more than just some rough quartz or basic glass for the optics. Having a spyglass should feel a bit magical given its "power", and building one should feel like a bit of an achievement. Given true boats and more aquatic opportunities are on the horizon, I feel this could be a useful addition at some point in the future.
Thanks in advance for your time.