Where are the Von Neuman probes and why aren't we seeing Dyson swarms around other stars yet? A) we are pretty much alone B) we don't have the technology yet to view other alien civilizations. I'm going with B. We need bigger and better telescopes in space to start really seeing what is going on out there. We will have this technology soon.

Getting from one star system to another is difficult. We are just on the edge of having the technology to send small probes to somewhere like Alpha Centuri in a person's lifetime (Breakthrough Starshot).

Listening for radio waves is a dead end since radio waves disperse rather quickly in the vast distances. Plus, any advanced civilization would be using compression and encryption which turn radio waves basically into garbage you can't distinguish from real background noise. Lasers are the answer, but they are hard because you need to be in line of site to pick up a stray signal.

Short of having aliens land in front of you, I think it's going to be very difficult to find them but I think we will have a much better picture within the next 50 years!