Isaac Arthur has a whole series of podcasts that cover all the current ideas around the Fermi paradox, which ones are more or less likely and why. Really interesting stuff. Here's a link to his Fermi Paradox playlist on Youtube: https://www.youtube.com/playlist?list=PLIIOUpOge0LulClL2dHXh...

He's also got a Soundcloud for audio-only format and a Facebook group.