Contact groups lost in Monterey upgrade

Aha! Another follow-up here. I decided to start making new groups and re-sorting my contacts. I hit "New Group" and suddenly all the groups appeared. Why hadn't I noticed they were there before? Because they were all off the bottom of the screen. I had a position bar at the side of the group column that was about one-fifth the height of the column. If I dropped down one bar's height, there was nothing in the column. If I dropped down until the bar was positioned in the middle of the column, then the top of my list of groups showed up. So the groups column is divided into five sections, and all my groups are shown in the bottom 2 1/2 sections. The top 2 1/2 sections are completely empty. Well, it's usable, even if inconvenient. Any idea how to get rid of that big blank section between the top of the groups column and the beginning of my list of groups? Thanks!

Nope. It doesn't show any groups. The app came up with the groups shown, so I "hid" them, then showed them again. Nothing. The only groups shown (if they are groups) are "All Contacts" and "All iCloud".

Okay, two further wrinkles. First, I discovered that the reason for the big visual gap between the top of my groups column and the beginning of my list of groups was a whole bucketload of invisible "null" groups with nothing in them. I deleted these, and brought the list of named groups up to the top of the column.

Second, when I look over my list of actual contacts more carefully, it appears that this version of my Contacts file is about two years old. All the changes made since then aren't here. A survey of my files doesn't reveal any alternative, more up-to-date files that I could link to instead. Is there a place to look? It appears that the system upgrade put in a new version of Contacts but didn't bother to locate the latest version of the previously stored data.

I could use a little help here.