I am having a very similar issue, I remeber not setting the link-mtu. Hope this works for me too.
--edit--
my issue was the internal service was blocking with its firewall rules.
In the vast majority of cases were looking at less than 10 using RDP or small file access. Occasionally some EMR software. I wouldn't expect more than 10-15mbps peak throughput.
You may have run the wizard multiple times without removing the former settings.
Is the client really connected?
The first 2 rules here belong to the WAN interface. Are there identicals? There won't come in any packet on OpenVPN interface for destination WAN address.
I'm having your box already from 2 months. Make two comments this time here at your forum. looks like this project is proper death community. Any of my comments was never answered.
Enjoy and thanks you for your no effort nothing