I re-ran the same client connection test. Same error on the client.
New server logs attached with Normal logging.

Which log level do you recommend then?

Alright. My bad. I will attach the server logs

Server logs attached

Current client logs, 7-zipped.

Client side logs show the same error and not much else for the aboe 2 examples:

Client connection test 2 - Try a direct connection

OK. I think there has been some more confusion here, but I will clarify. :)

This is only partially correct.

Alright. The issue remains the same though. In both configurations either the WAN or LAN clients con't connect as expected.
Let's focus on Example 1 since you reported this should work properly.

This issue is NOT caused by "A server ping exceeding 999 milliseconds when hosting a LAN is a normal occurrence. This is because the server is not accessible from the internet and we cannot accurately assess ping times using private IP addresses."

FYI
I can work with you on any configuration changes on the server or network that you may need to test OR to create additional logging info, etc.