Where are the aliens?

The SETI program has turned up very little in the way of alien or interstellar signals, while notable researchers, Carl Sagan, Avi Loeb, etc. have championed the Fermi paradox - and the fact that billions of potential Earths are definitely within our own galaxy, yet we still have no radio signals or "fog-horns in the mist" so to speak. Could it be that our radio spectrum is relatively archaic in relation to technologies that are evolutionarily superior? Could we be missing alien TV broadcasts within a different spectrum - say the high-frequency gravity wave spectrum? And shouldn't we consider that even extinct species on remote planets would have likely left a perpetual beacon - like a lighthouse to signal that they once existed? Wouldn't that last action by a dying race be something an advanced intelligence would do? Or maybe they would broadcast a looping data-stream with their collective history and knowledge into the cosmos? Or, should we instead look into the quantum realm for their remnant consciousness? If the quantum realm underlies all reality - ours, theirs, Gods, etc., would we find their presence in there instead of "out there"?