Like many people in the TTRPG space, I find Mike Shea's Return of the Lazy Dungeon Master to be a very valuable tool when planning my games. That being said, I think its fine (fun even!) to get lazier than is prescribed in that book.
Recently, I read The Copy and Paste Manifesto from the blog Rise Up Comus (a favorite of mine), and it got me thinking about how streamlined I've gotten with my DMing, especially with my online group. The ethos of the blogpost is that, unless you are creating something to publish, it's totally fine to just grab other people's materials and drop them into your adventures, without any modifications.
I like to blend the ideas from these two sources of DM advice, where when I am thinking of potential 'scenes' that I can use in an upcoming game, I'll often just grab a scene from a book or a movie I like and do that. For example, last winter I had Father Christmas ride by on his sleigh and give the heroes some magic items, exactly as I remember it happening in The Chronicles of Narnia. Similarly, I've dropped the encounter with the trolls Tom, Bert, and William (sans names) from The Hobbit into my games.
Generally, I do not spend more than 30 minutes planning a session, so using an abbreviated form of the Lazy DM's 8 steps, and borrowing liberally from a myriad of sources is essential. I don't have much other reason to write about this, other than to say that when you're an adult and don't have a huge amount of time to plan games (and if you're like me, where the games you do get to play are never for much more than an our and a half), you are probably fine stealing and improvising as liberally as possible. You don't need a sprawling web of rumors and NPCs catalogued meticulously in an Obsidian file, unless that's what brings you joy with the hobby. Just play the game and make it up as you go. Your players are probably too busy doing a funny accent to notice.