I think you might misunderstand me. I'm not saying I want more crunch, or that I'm uncomfortable making rulings, or that you're a bad wrong DM for doing so. I'm actually very comfortable making rulings and inventing stuff -- it's part of the fun of the game, for me.
What I'm saying is: I want to know when and under which circumstances to do these things. Like, here's some text from a game called Wanderhome, picked randomly from my folder of PDFs.
View attachment 261907
This text explains how to start playing the game. It's a bit vague about who gets to say what (maybe a flaw, but whatever), but it's pretty clear that you start the game by establishing a scene as a group, and gives you some tools to do that.
In 5e, establishing the location is a DM's responsibility, I guess? I'm fine with that. How do I do that, though? Am I allowed to start my PCs in a jail cell with no stuff, or do they get some say in it? How do I decide if and when monsters attack? Can my players influence where we go in the next scene, or do they have to go where I tell them?
This is the kind of basic stuff I'm talking about when I say 'joining the dots'. Experienced DMs will have their own answers to these questions, but new ones often struggle.