Installed Wireguard and luci-app-wireguard. Seems OK. However, the next step is:
Creating a Wireguard interface
To create a new Wireguard interface go to Network > Interfaces > Add new interface… and select “Wireguard VPN” from the “Protocol of the new interface” dropdown menu.
However, I do not see "Wireguard VPN" as one of my choices. Did I forget a step?
The output should indicate that the packages are already installed on root. But if it says anything else, hopefully it will manage to complete the installation this time around. Make note of any output and update the thread with anything of interest.
EDIT: in my experience thus far, installing via CLI, just the two packages I referenced are sufficient to install all related dependencies. But you could also install everything explicitly as @lleachii suggested in that post.
root@OpenWrt:~# opkg install wireguard luci-app-wireguard
Package wireguard (1.0.20200506-1) installed in root is up to date.
Package luci-app-wireguard (git-20.136.49537-fb2f363-1) installed in root is up to date.
However, there is still no VPN choice in the Interfaces > Add new > Protocol dropdown
Da! Needed to reboot, now Wireguard VPN shows up in Interfaces > New > Protocol
Sorry!