We have been working for a while in a new
network-manager snap based on upstream version 1.10, and with Ubuntu Core 18 base. This work is now quite mature, but we would like to do more testing before releasing to the stable channel.
If you want to give it a try, you can install the current release in beta with:
snap install --channel=1.10/beta network-manager
Please let us know how it works for you.