Apple Photos (Mac, iOS, Apple TV, iCloud)

I recently moved onto a new machine and in addition, moved my photos + library – which were on a small external SSD – onto a new, bigger external SSD.

When I first opened Photos.app on the new machine, I held down option and chose the newly located library (which is about 950mb in size, which is fine because I’ve copied photos across to it so they’re available in icloud memories etc)

However, I get this message in settings “This LIbrary isnt searchable in Spotlight due to its location” then it links to an Apple help link:

https://support.apple.com/guide/photos/PHT211DE786/8.0/mac/13.2.1

What it says makes sense, but I dont understand why the newly located library cannot be deemed the system library? It worked before with an external drive.

I really don’t want to have to delete the library file and rebuild it – will take weeks and I’m concerned about duplicate photos in icloud

Any suggestions? Has the move to a new computer + library location screwed things?