There is a simple answer to the question of radio signals. We have been transmitting 'analogue' signals for about one hundred years. Once everything is 'digital' transmissions it will look like random noise from far away. So for two equivalent civilisations to communicate they must be on the same timeline as far as their development is concerned. These windows are very short and very unlikely to coincide in time let alone within range of sensitive detectors. .
I personally think the Universe is teeming with life. Thankfully far enough away to not cause us any grief. Yet!
There is no definitive answer as we have no evidence only conjecture.
Should be interesting.
Bert
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