Make an infinite water source, if you don’t have one then you’re going to have to go cave digging to find water. If you have access to water you can create obsidian and kill endermen in the Nether so no need to go above ground really. Cattle is important too. I actually installed a modpack a few years back that made going onto the surface a death trap with overpowered mobs everywhere, your hunger draining by 3 every minute and to top it off, the sun did damage to you and the entire overworld was in a permanent dark red. It became trivial once I lived underground. It teaches you a lot about how to survive pretty easily, just use common sense and mark your pathways appropriately when you’re mining or you’ll get lost. If you get to the point of having so much iron you don’t know what to do with it, set up a second underground base a few hundred or thousand blocks away and bridge the two together using a rail system. It’s good to have multiple bases that are decently far away from each other for maximum resources.

Yeah, pretty much. Just that and a mine and your set for life. Don’t forget the bed.