How big should a Contacts Archive be?

After losing a few critical contacts for an unknown reason, I started doing a weekly archive of all of my Contacts as suggested by Apple Contacts User Guide. However, having been doing this for over a year now, I am questioning what has happened. Looking at all the archives going back to the start of my archiving folder, they started at around 40MB and then suddenly they were around 150M. And lately they are around 14.5GB. After playing around I discovered that if I select Export > Contacts Archive, then quit Contacts, I get a small file. If I leave Contacts open for several minutes I get a bigger file. If I leave Contacts open for a long time I get the 14.5GB sized file. This is a consistent size if I leave Contacts open while doing and archive. So that tells me that the smaller files are likely worthless. Contacts gives no indication that once you start the archive it takes many minutes to create the archive.

However, I am concerned that my Contacts database, which I have had through many MacOS releases for at least 15 years, is now corrupt. That concern is because when I look at the package contents of the large contact files I am seeing what appear to be duplicate files. Of course I don't know what I am looking at nor do I know what a good archive would look like.

Contacts shows I have 507 contacts. I am using iCloud. I was storing the archives in a folder in iCloud Documents. But I have recently decided to store them in a folder on my external SSD. I make regular backups of this SSD. I could try using one of these 14.5GB archive files to replace my Contacts. But I am afraid of losing everything. I have exported everything as a PDF. I see I can also export to Numbers.

So how do I determine two things? First, is my Contacts database corrupt? I see odd things happen on a regular basis, such as duplicate entries randomly appearing. Second, what should the size be for a valid archive? Is 14.5GB appropriate for 507 contacts?