systemd-NetworkD Support for DHCPServer is limited based on https://www.freedesktop.org/software/systemd/man/systemd.network.html#%5BDHCPServer%5D%20Section%20Options
However, you are probably better off with it
ISC DHCP server If you need to tune multiple DHCP subnets simultaneously or provide advanced DHCP options and the like.
I have an LXD network that uses an 18.04 container that provides DHCP to all other containers on this subnet. It seems to work
netplan DHCP clients.
Note that in either In any case, the DHCP server should have a static IP address outside the DHCP pool. This way, the server behaves consistently.