In the original formulation of the Fermi Paradox attributed to Enrico Fermi and Michael Hart, the question was, with billions of stars in our galaxy that can support Earth-like planets that can in turn support intelligent life that can eventually invent interstellar travel that can traverse the galaxy in a few million years and therefore Earth should have been visited by extraterrestrial beings several times but "where are they?".
A new paper by Carroll-Nellenback, Frank and Scharf shows that the stellar motion of galaxies means that a galaxy can be settled in less time than what was originally computed but this also doesn't mean that extraterrestrial life forms aren't there. In the new paper's simulations, settlements can appear and disappear. I remembered the YouTube video that showed all the existing civilizations that appeared on the face of the earth and when you look closer some civilizations can be on the same continent never meet.
Also, not all settlement endeavors last for a long time. Also given finite resources, even an interstellar-able would have to choose which star system to go to and pick a habitable planet. There's also the Aurora effect based on the novel of the same name where the colonizers do land on a habitable planet yet the colonizers still don't survive.
Or maybe advanced civilizations encrypt their communications just as we have started doing and that's why we can't detect them.