This error will appears when you will try to explore you phone paired with computer.
What I tried new system installation, on UBUNTU/KUBUNTU 18.04 and 18.10 error /run/user/1000/592bbfe835d2ed5c/storage/emulated/0 does not exist was the same. So problem is not on computer side.
On my S8 phone KDE Connect app was in Version 1.10.1 . Downgrading to Version 1.8.4 solves all problems!
This app can be found on fdroid page , https://f-droid.org/packages/org.kde.kdeconnect_tp/ . Just download app via mobile browser and install on the phone. I had to pair and give permission for file browsing in KDE Connect app in my phone.