You are correct, in over 90% of the cases of rebooting your mac, access to local network devices will be forbidden by Sequoia. For users who have a mac dedicated to Roon best to leave it permanently on. For those who like to shut down their mac overnight then this process (in my experience 9 out of 10 times) will be required after a restart.
It seems like, after a reboot, the system in Sequoia to permit access to local network devices for those who experience this issue either does not start, crashes or freezes during the start-up process. Toggling off and on the Roon entries in local network seems to force a restart of the access permission system. Then closing and reopening the Roon server app forces Roon to re-scan the network so you can regain access to the local network endpoints once access permission has re-started…