Time travel brain breaking

I've played around with a few different time travel stories, fics, chapters, now. Actual time travel or more on the timeline-altering alternate universe side. And every time I say to myself, No. No more. This is too hard. You have to stop. And I don't stop. In fact, I'm doing it again. So I need to ramble about time travel for a while. There are so many many different types of time travel. I'm specifically interested right now in a deliberate moving around in time vibe. So in brief, to my mind, these are the main ones I think of, with other stuff being flavours or variants: Fixed is where everything already happened. It's all inevitable. A closed loop. If you try to change something bad you'll probably find you caused the bad thing. You can't shoot your grandfather because you didn't shoot your grandfather because you wouldn't exist to do it if you had. Branching is multiple universes. Changes create new timelines. Infinite timelines and realities. If you shoot your grandfather you're…