Is the OpenVPN plugin still on hold/cancelled for OMV6?
Did you read post #2 on this thread? I have used openvpn in docker and see little reason a plugin is needed.
Is there a reason why openvpn has been abandoned?
Because it was a painful plugin to maintain. Feel free to maintain it.
wireguard is 100x more complext to setup than open vp
As someone who has worked extensively on the openvpn plugin and the author of the wireguard plugin, you have this backwards.