There is a known issue with Apple’s updated security in Sequoia and Roon. Have you tried this workaround that usually resolves the issue (but is needed everytime the Mac is rebooted):
Typically you only need to toggle the setting from On to Off and then back On, I do not need to reboot my Mac Roon Remote after making this change to see Roon over my network (my Roon Server is a W11 PC).