Thank you for the update and letting us know the driver is now added!
I installed and tested the beta24 version and now my Ethernet port works!
Happy Happy Happy
Go to "Tools" | "Update OS" in the GUI, and in the branch section select "Next" and you will see the beta version available.
(Only recommended for testing purposes)
Update:
I just installed Unraid 6.9 Beta 22, and the Realtek RTL8125B onboard Ethernet controller still does not work on my Asus TUF Gaming B550 Plus motherboard.
I am having the same issue with this motherboard as well.
Is there anything I can do to help you test the new drivers?
I'm a noob, but I will help if I can.