Suggested image dimensions Gutenberg Hook

I just migrated to Gutenberg block editor and I simply love it. After migration, I saw a dimension suggestion for images when trying to select the featured image. The problem is that we already have some editorial rules about the featured image and the editors are following this suggestion instead of our suggestions.

I only want to change this value, but I couldn't find a hook to change these values to 1400 by 1400.