I decided after having issues with Centos 7 and Kernel 4.7 (needed for AMD Ryzen support) to use Ubuntu 18.04 which uses the Kernel 5.
So, fresh minimal install with gui of 18.04, Install Virtualmin immediately (no issues reported, install clean).
So far ...
1/ Nothing shows in Network Interfaces all blank, but interfaces do show in "active". Something to do with VirtualMin (still) not using Netplan, found instructions on turning Ubuntu back to "old method" but they flew over my head.
2/ Happens in Centos and Ubuntu. When running the Virtualmin install check, expects 127.0.0.1 in resolv.conf. This of course now gets overwritten every restart, and 127.0.0.1 vanishes. Where are you supposed to set this as a permanent entry for resolv.conf?
3/ (after install) Centos 7 - Disk temps all appear on dashboard, Ubuntu - they don't.
4/ This is probably more Ubuntu than Virtualmin but understanding the setup for Apache is so confusing compared to Centos. I'm surprised that Virtualmin doesn't use the same "setup" for both systems.