Hey friend,

I would try ruling out encryption by trying a basic tunnel. If you can identify that you get good speeds through an unencrypted tunnel, then you know the problem is specific to the configuration of the VPN protocol used. If you don’t get better speed through an unencrypted tunnel, then you know it’s more likely just that you can’t get better throughput to one of the datacenters.

This has suggestions on disabling encryption with OpenVPN:
https://superuser.com/questions/1194285/unencrypted-vpn-like-tunnel

Here’s an outdated article on setting up a PPTP VPN:
https://www.digitalocean.com/community/tutorials/how-to-setup-your-own-vpn-with-pptp

Note that PPTP is not considered to be secure and is not recommended for actual usage, I am merely recommending it as a potential avenue for an easy test.

Jarland