If the images still show a preview in Lightroom on your desktop, this might be helpful Script to extract previews of lost or deleted photos
Else I will give a try to locate images on the server.
This is unfortunately no solution for me. I had deleted the photos in Lightroom Desktop (Olafs iPhone SE > imported photos). The sync has then deleted the photos on lightroom.adobe.com.
I found the photos! In a TimeMachine-Backup:
Users / [User] / Pictures / Lightroom / Mobile Downloads.lrdata