I'm starting to wonder if the problem is ISP related (your internet service provider.)

Could you try connecting with LPE with Little Snitch temporarily disabled whilst testing the connection, disabling it before opening LPE? I'd recommend adding a fresh connection file: OSX LW connection installer - MediaFire Mirror.

I wonder if any of your gnutella programs will connect. Perhaps try FrostWire v4.

I tried Little Snitch some years ago but due to my ignorance removed it because I found it too naggy & problematic for all the internet apps I use.