Thanks, Nick.

The problem is that I don't think it is kmod compatible so for every kernel update you will need to recompile it.

Hm...Not perfect for production with automatic updates enabled. Will consider giving it a go just to find out if it sorts the issue. In the long term I might just leave it as it is and use the e1000 NIC as a backup due to poor performance. If I'm not mistaken IOMMU can be disabled as it's used for virtualization which I don't need. Another option would be to get another Realtek NIC and enable IOMMU.

BTW for all Ryzen users - update your BIOS (release with AGESA 1002a). Then enable "C-power states" if you disabled it to sort out crashes/hang out and set under "Advanced/AMD CBS" -> "Power Supply Idle Control" to "Typical current idle" - 18h up and running with this. Previously every idle (30 min or so) I had a crash. Looks like "Typical current idle" setting sorts it out and with "C-power states" enabled you have some C states / power saving features.