OpenVPN will let everything go via the tunnel so it is normal you cannot access your device. I am curious about the solution that previously worked for you. For me, I need a similar solution with OpenVPN to open a port for Transmission, not the WebUI, I do not want to expose the WebUI to internet. But Transmission works better with port 51413 open. Not sure how to do that with OpenVPN.
But to access SSH and SFTP, I do this:
RPi3 runs OpenVPN and transmission, local IP is 192.168.1.11. No port forwarding setup in my router.
Vero4k does not run OpenVPN. For this device I have setup portforwarding in my router: LAN port 22, outside port 9000 (could be any high number).
On my remote computer I have set up Putty like this:
Putty > SSH > Tunnels > add forwarding with source port 9000 and destination 192.168.1.11:22.
You can save this by clicking on Putty>Session and hit SAVE.
Now when I open the SSH session with Putty to my Vero4K, after logging in I run this command:
ssh osmc@192.168.1.11
Now you can login to the RPi3 which runs OpenVPN and Transmission.
While this session is open, I can even access the RPi3 with SFTP via Filezilla and also Transmission WebUI! For this you need to add the ports in Putty>SSH>Tunnels.