Sharing my entire library

As you had said the complete photo library can't be shared ( agreed ) , still the photos can be shared setting up photo library and its preferences in Mac and turning on photo box in iPhone https://support.apple.com/en-gb/guide/iphone/iph961b96c4d/ios

And moving complete photo library to an external hard drive , then https://support.apple.com/en-in/guide/photos/phtae4e05c67/4.0/mac/10.14

The photos will get transferred to system photo library folder of Mac photo application and iCloud photo library has to be turned off , as in normal signing with same credentials the albums along with photos will also be shared , it would not be risky , but what op desires share photos and don't want to share previously created albums ( that is not sure ) perhaps ignored to transfer photos using shared albums between iPhone / Macs .

Photos supports only the sharing of photos, but not the complete library.

To give other family access to your library, create a copy of of your Phots Library on an external volume. Prepare the volume as described here with the "ignore Ownership" flag enabled: (Move your Photos library to save space on your Mac - Apple Support)

Others can use this copy to browse your photos in turn.

You cannot share your system photo library directly, you need a copy of the library for sharing. The problem is, that your main Photos Library will be your system photo library, and the System Photo Library will always be in use by system processes, while you are signed into your user account, even if you are not using Photos. And it is not possible to set the "Ignore Ownership" flag on your system volume.

Complete photos are shared between devices if they are signed in with same Apple ID and password on the same network see this https://support.apple.com/en-in/HT201302

If you are talking about family sharing account https://support.apple.com/en-gb/HT208147

When you share a storage plan, your photos and documents stay private and everyone keeps using their own accounts with iCloud , and you have already cleared don't want to share photos using shared album .

If you have set family sharing account it has be disband or the family members have to leave the group https://support.apple.com/en-in/HT201081

And then start syncing the photos between devices .

I think, the question is about sharing the library with other family members, tygb, not about sharing photos across all devices. To share the library in iCloud like you described, all family members would need to use the same iCloud AppleID, that would not be practical, even risky.