Those are just formulae. It doesn’t take into account the logistics of getting humans (or aliens) that far.
Ten million years is the blink of an eye to stars, but not to functioning spacecraft and certainly not to humans.
To get to of the closest exoplanet we know of (and it’s probably not habitable for numerous reasons), Proxima Centauri b, at Parker Solar Probe speeds would take over 7000 years.
That would require a Generation Ship. (or Wiki) You’re talking about 80 generations. We are not even close to having the wherewithal to accomplish that. We can barely make cars that last 50 years much less 10 million years. That’s a lot to ask of a machine with working parts and especially if there is no place to get replacements.
But suppose we we did build one and got there, then what? It’s certainly not going to be habitable. How do we fix that? Depending on whom you talk to, terraforming Mars could take anywhere from 50 years to 100 million years to complete. It’s already similar to Earth and it’s right next door. Without resources nearby, terraforming exoplanets is virtually impossible. And they might not have a fuel source available.
Sending out spaceships with beings, getting them to another planet, terraforming it, building the infrastructure to build more spaceships is best left for science fiction.
Colonizing the galaxy in ten ten million years works in theory - not in practice. The oft used comparison to Columbus and early explorers colonizing the globe is not applicable to colonizing space.