video missing from iphone and icloud

I recorded a large video on my phone that was missing the next morning and was not on icloud. I saw a thread about how to find the video by backing up and restoring the phone with my laptop. Somehow the video is still missing from photos but the thread explained how to find the missing file after the backup and move it to Photos.

During all this deleting and updating I lost the thread and can't find it.

Does anyone know the procedure I'm asking about? Or how to find threads in this community I viewed a day ago?