I am you and you are me.

Second, that reincarnation frameworks usually also include a structure where it's not random what you reincarnate as next time around. Karma doesn't usually boot people back down to bacterium right after human. It's usually more of a leveling up in order to experience deeper and more meaningful lifetimes. But YMMV.
That sounds extraordinarily arbitrary. Who decides what counts as a "level up"? Does that mean if you start as a bacteria you're stuck like that for a few thousand or million cycles? How would you earn enough karma points to level up from being a bacteria? What counts as "deeper and more meaningful lifetimes" if you are a bacteria?