Do not set the thumbnail intentionally

Hello.

I am considering installing a plugin.
Is it possible to make it work without intentionally setting the thumbnail of the article?
When I manually delete an auto-set thumbnail, it is automatically set again after saving.
It would be nice if you could check the status of the thumbnails before the update, and if the thumbnails are deleted after the update, it would be possible to make it not to set them automatically.

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