According to the Armbian (one distro to support them all:^) page, mainline kernel support is complete, although they say there still could be some network problems. From what I read on their forum, the Hardkernel Ubuntu-based image is currently more stable than the Armbian one.

https://www.armbian.com/odroid-n2/ https://forum.armbian.com/search/?q=odroid%20n2%2B&fromCSE=1

https://wiki.odroid.com/getting_started/os_installation_guid...

Dietpi also supports the N2, which is very similar to the N2+. https://dietpi.com/