The Earth might flip over at any time

That phenomenon depends on a particular arrangement of axes and mass, it does not happen to all shapes, and there's no reason to believe Earth is super-weird-enough under the surface in a way which we've never detected in gravity surveys.

https://en.wikipedia.org/wiki/Tennis_racket_theorem

Rather, this submission sounds more like a variation on:

https://en.wikipedia.org/wiki/Cataclysmic_pole_shift_hypothe...

> There is evidence of precession and changes in axial tilt, but this change is on much longer time-scales and does not involve relative motion of the spin axis with respect to the planet. However, in what is known as true polar wander, the Earth rotates with respect to a fixed spin axis. Research shows that during the last 200 million years a total true polar wander of some 30° has occurred, but that no rapid shifts in Earth's geographic axial pole were found during this period.

As a teen, I read an SF book with this premise, https://en.wikipedia.org/wiki/The_HAB_Theory .