I could imagine it being a problem going right through the center of the galaxy. But even if you go all the way to the other side around the edge, that's still not even 1/4 of a million light years. There is nothing "millions of light years away" that is inside the Milky Way, even by a convoluted path. Even round…

For me the "Great Filter" is just the speed of light. Life could evolve, we could get civilizations in other solar systems, even in our same galaxy or local star neighborhood. But detecting us, caring about us, existing at this very moment, or even trying to get here, no matter how much they are around, have very low…

Because it would only take about a hundred thousand years to colonize the galaxy even without faster than light travel.

On the contrary, would you say particles that know they are being observed so use more energy to be observed is total fantasy?