For anyone in the future - this worked for me. (I am not sure if it was a combination or the last thing I did)
Network and Sharing -> go to your adapter -> click properties -> turn of Ip-version 6.
Restart Comp and Launcher.
This did not work for me until I ran the launcher in Administrator mode.
If you don’t know how to run it in admin mode; right-click launcher icon in taskbar->righclick ‘epic games launcher’->select ‘run as administrator’.
If not in taskbask - just rightclick the icon and select ‘run as administrator’
I have run it as admin before but it still had the asset pack as unavailable - hence my statement that it ‘might’ be a combination of these.
Hope this helps.