Contacts missing after IOS update 18.6 - Iphone 15 Pro Max

Out of a sudden, some of my contacts were randomly removed overnight from my phone and they are not available anywhere even after restoring a backup from several days ago. Did not remove any emails or do any changes to my phone as the update happened overnight and once I woke up, I immediately noticed contacts missing as I had messages from unsaved numbers which I had the day before like my wife...

I've done all troubleshooting steps available and no solution so far. Pending apple software engineer feedback after issuing a support ticket and the first two support employees weren't able to solve this.

Will keep you posted. Anyone faced similar issues and found a solution yet?