Hi @rawathletics,
I hope you are well today and thank you for your question.
You have to develop custom code to display Recent Posts widget same as it looks on the Illdy theme but you can display the thumnbnail on it by using the custom plugin solution shared in the following topic which is working fine for me.
https://colorlibsupport.com/t/thumbnails-of-recent-blog-posts/#post-63837
Please make sure you have set featured images to the posts.
Best Regards,
Movin