I do not run PMS on a Mac, so unsure how well the Apple migration works for Plex.
The traditional method of moving between servers is outlined in Move an Install to Another System.
Note that if you copy the plist file (mentioned in Copy Additional Server Settings section), you cannot run both servers at the same time, as they will have the same name and ID.
If you skip copying the plist file, you can run both servers at the same time. The new server will have a different name and you will have to re-pin libraries on your home page, re-share (but not re-invite) with anyone you share with, etc. The advantage is that you can run both servers at the same time, migrating traffic to the new server when you are comfortable doing so (no hot cutovers).
If accessing both servers remotely and using fixed port forwarding, you will need a second port forward statement in your router using a different public port numbers (the internal port is always 32400).
You can modify the nsmb.conf file on the Mac or use NFS instead of SMB.
See Plex Files Unavailable but they’re not missing
