Sounds like maybe an issue with the VPN restoring from the backup maybe?Had a weird bug when I tried to restore from iCloud. 12 Pro backed up my iPhone X and then restored from that. Well when it finished, WiFi wasn't staying connected and I have poor cell coverage in my area so I knew the restore wouldn't complete. Looking at the settings screen, you could see the toggle for VPN flickering on and off. I use Private Internet Access so I'm not sure if there was an issue with the VPN even though it wasn't downloaded yet.
I then erased the phone completely and did the restore except this time I did it directly from my iPhone X via direct transfer. Fixed the problem and its downloading the remaining apps now.