One of my most popular non published Add-ons is First Slide. This allows you to push slides to student Google Slides and to also grab the text off of their first slide so you can quickly read and give feedback.
The answer is always a spreadsheet. First Slide is an Add-on for Google Sheets. After making a copy of the spreadsheet template, use the Add-on menu to show the sidebar for First Slide. Click the button in the sidebar to choose the folder you have in Google Drive that contains student Google Slides.
This will import a list of all the slides in the folder along with what the students wrote on the first slide.
There are columns that are imported along with the student slide titles and slide text. Slide URL, Title, and Slide ID. You probably do not need these columns, but please do not delete them! They are important for the Add-on, but they get in my way to see student responses.
Highlight columns E, F, and G and right click to choose “Hide columns.” This helps make them out of sight and out of mind!
Use the Reuse button in the sidebar to send the feedback you wrote on the spreadsheets back to the student and also to push slides to the students Google Slides. I have also added the ability to pull all the text from all the slides and not just the first slide.