I ran into this situation as a Google Workspace admin and this response is geared towards Google Workspace admins who are trying to track down a form owner.
The Document ID in the form link would be here → https://docs.google.com/forms/d/e/(Document ID)/viewform
You should usually be able to take the ID from the url and find it in https://admin.google.com > Reporting > Audit and investigation > Drive log events and search using the Document ID. In my case the form I was asked to find the owner for was not returning results here.
The next thing you can do is submit a dummy response on the form then go to https://admin.google.com > Reporting > Email Log Search and search for "Response" with results for only Today.
It'll take a minute or two for it to appear in the logs but there will be an email titled ""[Your Form Name] (Responses)" was edited recently" at the bottom of the results. The recipient shown here will be the person you want to contact.
Adding this response because if I just accepted Google Support's response I would've thought there was no way to find or access the original form. It turned out to be on a Shared Drive I had access to so I didn't need to request access to the form itself or anything.
From there it was straight forward to add others as collaborators to the form once I opened it up.