MacOS Contacts backup

You would be much better off exporting your contacts to a vCard,VCF file. Others in the support communities have found Abbu files are much harder to manage from old to new operating systems.

Open the Contacts application.

Make sure View menu -> Groups is not hidden, if it is, show the Groups.

Select All Contacts

Select File menu -> Export -> Export vCard

Create a new folder on your desktop called my Contacts export, select it, and then while you see its empty destination, hit save.

That will put all the vCards either as one file or one file per contact.

Pick other groups and put them in folders in Finder of their own if you want to separate the groups in the export.

Once you have one that, you can backup the data with either Time Machine to another drive at least twice as big as your original, or use one of the other methods of backup suggested here:

Backup now, or forever hold your peace - … - Apple Community

You can't restore a Contacts Archive. Export as vCards.

Since you can't keep the group assignments, export everyone in each group, ending up with as many vCards as you have groups.

I will also add under different systems, it may export all the cards at once, or just one. Some you select command-A to select all the cards out of the group selected and then Export once all the cards are selected.

Some you have to drag and drop them into the folder one by one.

Depending on your Mac OS you may find one is easier than the other.

My 8800 Monterey contacts for instance once exported took about 2 MB.