Looking into the networking problem I found that Windows broke on the back end. Not sure what broke exactly, but after a reset of the Server PC everything worked, local and remotely. I backed up and rebuilt my Plex server before writing this post to ensure all repairs were good.
I want to note some of my findings while troubleshooting
I found Asus routers do have DNS Rebind Protection enabled and is not able to be turned off within the stock firmware. I highly recommend installing the Merlin firmware for Asus routers for the ability to turn off DNS Rebind Protection.
Check your firewall rules within Windows. Apparently Windows updates will change them.
Backup your database. Plex has an article about how to backup and reinstall your data. This has all your watch data and viewstats.
I reset Windows after this. After the reset and setup of Windows I reconfigured Plex and found everything was working. Reinstalled my database backup and metadata to a fresh working Plex.
Massive thank you to @sa2000 for your patience, quick responses and troubleshooting skills with this matter. I could not have done this without your help.
Problem solved.
