Actually we’ve got a solid answer to the Fermi Paradox: space is big, no bigger than that, and traveling through it even at the speed of light is very very slow. Assuming our very first radio transmission were out there in a way that was receivable (it isn’t, it was strong enough, but pretend), less than 1/10 of 1% of the volume of the Milky Way would have been “exposed” to that transmission and thus have the ability to find out humans exist. And of course that’s just THIS galaxy, there are more other galaxies in the universe than there are stars in ours, and none of them have a chance in hell of ever finding out we exist (well OK, I suppose we could do something that made a big light and they could see it billions of years from now). Alien races could be “next door” in the scale of things and never find out about us, or vice versa.
Then of course you have all the other potential problems. But really, space is big, “they” could be all around us and nobody knows about each other.