How to combine 1 fast WAN w. private IP and 1 slow WAN w. fixd public IP for VPN

[handarbyte]

Hi everybody,

I'm the new guy!  :)

So here's my first strange question:  ;)

At a customers site (in Germany) we get only

1. LTE (speed OK, but only dynamic private IP) and
2. DSL (very slow, but fixed public IP).

Does anyone see a way to combine the speed from LTE and the IP from DSL for using it for OpenVPN access?

Thanks!

Thomas

p.s. I know mdex.de (they provide fixed IP via OpenVPN tunnel for exactly this purpose), but there are monthly costs I'm trying to avoid.