Great troubleshooting you’ve done so far!
Please follow the steps in Adding Application Exception to McAfee Firewall to add Roon as an exception to the firewall.
Additionally, you can try changing the router’s listing to a Home network in McAfee: Mcafee Firewall settings for Roon 1.7 - #7 by Anthony_Lombardo
A third solution is to change the security level of Roon and RAATServer: SB3 won't connect to Roon Sever with McAFee turned on - #9 by Jeff_Barham
Let me know if any of the above work for you. 