Cannot externally connect to minecraft server

I am trying to set up a dedicated minecraft server that I would like to be open to the internet.
I am able to connect and play just fine via localhost, however once I try to connect via my computer’s IP (to verify others can connect) I get the error
io.netty.channel.abstractchannel$annotatedconnectexception
I have set up port forwarding on my router, which when I test with sites like canyouseeme shows the port is indeed open.
I’ve added TCP and UCP inbound and outbound firewall rules for port 25565, as well as rules for the minecraft launcher, and opening up the rules for java too.
I’ve even tried disabling my firewall and testing while still getting the same error.

I’m out of ideas of what could be causing this, especially given that other sites can see my port 25565 as open.

Thanks in advance for any help offered, this has me stumped.