Merge 2 photo libraries on Mac

[jnat88]

For some reason my Mac split my photo library in 2. How do I get these merged back together?

I tried some fixes I found online. Mainly exporting the one library to a folder and then importing the contents into the other library. This causes my computer to freeze/crash each time I try and I’m guessing because of the size of the file.

Any help would be appreciated! Thanks