How “easy” is it to DM a tabletop RPG?

by “easy” I mean your only tabletop RPG experience is D&D and youve played it maybe 5 times total as a player not a DM and you wanna try and DM and completely different RPG (that no one else in your group has played so theyd be as new as you are. So it wont be like Im a newbie DM trying to DM for a bunch of D&D vets that probably know the game way better than I ever would)

Also do you have to go all outwith minis, drawing dungeon maps, thinking up and writing/creating a full story/campaign or is there a “lighter” way to play? I mean not everyone a writing and dungeon designing genius Im sure, how would they DM an RPG if they want to? I mean if you have just the books for example do they have enough pre made stories, campaigns, dungeon maps, enemies etc etc you can use instead of having to dream up your own?