I have a MacBook Pro running Catalina and a Photos library. I also have an iMac running Catalina with an empty Photos library. I want to have the same Photos library on both computers. How can I do this?
I simply want the same library on both computers.
The best way, by far, is to simply use iCloud Photos. This will put your Photos library in the cloud, and then you will see the same library on both Macs.
Otherwise, if you copy the entire library onto the other computer, they will be out-of-sync the second you add another photo or make any change to the library. There is no way to keep them in sync.