There are two issues here. Firstly,
I’m using 33110 to connect – where should I be forwarding this port to on the server side?
You are forwarding port 33110 to port 22 which is for SSH connections. To connect using NX you need to forward it to 4000. You can read more about ports here: https://www.nomachine.com/AR01L00770.
Secondly,
Running NoMachine sessions over a SSH connection is not supported on this server. Do you want to switch your connection to using the NX protocol?
“SSH not supported” should not appear in the case of the Workstation since SSH is supported in this product. What did you install? Did you perhaps install Workstation over a NoMachine (free)? If you did, uninstall, remove the directory /usr/NX before reinstalling the Workstation.