Low-prep "plug and play" DMing

Hello everyone! I don't have much experience, but one thing I learned while playing Troika! with my friends is that the more I prep the more forced the game will feel (at least to me). I think it has to do in part with the fact that I will more or less voluntarily try to steer players towards content I prepared (it's some kind of sunk-cost fallacy I think) and in part with me kind of knowing what to expect, making the game less enjoyable to DM. The best sessions have been the ones where I had two or three ideas and winged it, building upon what the players did or said and generally improvising. The biggest con to this approach is that it's hard to keep everything consistent and I'm constantly afraid of contradicting stuff I said before or just plain forgetting it. I want to start taking notes, but I'm also afraid of being distracted from the players while I jot down stuff. So I ask you what are your tips for a more immediate, "plug and play" style of playing. I'm not too interested in having a balanced game or telling intricate overarching plots, and I enjoy strange situations that require creative thinking the most (plus cool worlds and creatures/NPCs). I would love to find a way to start playing out of the blue like one does with boardgames (well, the casual ones everyone plays)