If i use one of those port checking websites it says 8333 is Open but
https://bitnodes.earn.com/ says Not Reachable
does anyone know what Im missing here?
Let's start with the obvious: did you portforward port 8333 in your modem settings to the IP address of your Ubuntu?
yes
Do you use a VPN or have a service that monitors your network traffic (a "physical firewall" for outbound/inbound data).
Since you're still getting connections, what does it say at the bottom? Is it still syncing or is there another error. 8 perrs seems about right.
If you're still stuck after this, I'd suggest you try and change the port to something else (22 would be my suggestion - it's usually for SSH so should be available unless your router already uses that port).