I have a 'main' list that needs to be looked up from other SP lists (ex. customer name column). The other SP lists are not within subsites where the 'main' list was created, they are in other separate sites. Site columns don't seem to support this as they are only visible to children subsites.
Is there a way to achieve this with metadata, content types or do I need to duplicate the data in all sites and using a flow to keep everything in sync ?