Error in featured image generation

Hello,
I have a problem with the featured image generation in posts imported from my feed.
I tried to set the “Post thumbnail source” to “Generate from the first post image” but the mechanism inserts the banner as first image.
I tried setting it to “Generate from media attachment thumbnail” but it doesn’t set the imported image as Featured image.
How can I solve the problem?

The feed is the following: https://ilsaronno.it/category/comasco/feed/

Is this possible with the Premium plugin? I am currently using the Lite version to try.

Thanks

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