A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi Ddigiro1,
Thanks for posting in the community. We are happy to help you.
To my knowledge, there are no out-of-box SharePoint features that will directly address your needs. You will need to build a Power Automate flow to check existing list items with the same UNID, create a new list item (row) with the merged values, and then delete the original list items.
In this case, since our team focuses on queries about SharePoint's built-in features, and we have a specific channel Power Automate Communitycoping with such building flow questions, I recommend you post a new thread there for expert help.
Sorry that our category may have limited resources on checking on your concern further.
Thanks for your understanding.
George | Microsoft Community Moderator