Go for real life with the Size standards, imagine a big hunk of rock that has like 50% Iron Ore in it, make it 25³cm³, kinda like a standard Ruler in size in all directions. If half of that Block was possible to be refined to Iron, you could make a handful of Tools with that easily. But if you were to make an Anvil out of it you would probably even run out when using just one Ore Block.
The point of this is that things like Nails and Barrels and all the convenient Stuff, needs to be cheap to produce when it comes to raw resources, so you can actually use them “wastefully”.
Nobody would want to craft a Crate if it costs an Iron Nugget worth of Screws, that would be a waste of Iron in MC, but in my Game I want it to just be a little bit of mining Effort and processing. Not to mention Armor is something that would consume a lot of Iron to be made, and things like Arrows would be consumables made of Iron Tips too.
The higher you go in Tech, the more Iron you consume, and the more mining needs to be done. And the first Iron Mine usually is not depleted until you reach a higher level.
You are not supposed to carry a shitload of Iron Ore on you after a big hour long Mining Session, like in Minecraft. You are supposed to find Iron, grab what you need and bring it back to base (or build a smelting base closeby), and you are set.
Also because of the other post with RNG Mobs, I will also do procedurally generated Ores in some way as an option, so you dont always have to deal with Iron and such. but every Place will have its own Earlygame, Midgame and Lategame Ores for sure, so you can start your Game anywhere without having to worry about being stuck in stone Age forever. (Said Materials will vary slightly in Abilities so it might be a good Idea to trade them, or even alloy them together to combine their Effects)