It makes a big difference if you're using a game engine or not. In my case, I'm hard-coding everything, so while setup of something that uses arrays in Godot or Unity might be a piece of cake, it's a lot harder when you're trying to accomplish the same thing from scratch. There are a lot of game engine "built-in" mechanics that I think a lot of developers take for granted.
You're right about text adventures -- if you don't have lots of content they can be really hard to make. I remember reading about some of the more popular text adventures in the App Store and a lot of those have word counts of 100,000 or even more.
So roguelikes use a lot of random number generation? That's another area I've found unexpectedly frustrating. You can tell the game to pick random numbers between 1 and 100 and after a while you start seeing some patterns. From what I've read, it's very hard to achieve "true" random number generation.