Go to Dashboard > Elementor > Custom Code. And then add this code to make the whole space/box/card of the post widget to be clickable.
Note: It does not work on new posts that has been generated by ‘Load More’ or ‘Infinity Scroll’ pagination.
IMPORTANT
You have to set the post CSS Classes to post. But if you forgot and it works just fine, then it’s fine.
If you want the whole box to be clickable on popup as well, add this to Elementor Custom Code as well.
The whole box, including the excerpt is clickable. But in this case, all example posts are linked to the main site.

This Is an Example of a Post With Relatively Long Title
This is a post that was posted on WordPress. It could be said that the

This Is an Example of a Post With Relatively Long Title
This is a post that was posted on WordPress. It could be said that the

This Is an Example of a Post With Relatively Long Title
This is a post that was posted on WordPress. It could be said that the

This Is an Example of a Post With Relatively Long Title
This is a post that was posted on WordPress. It could be said that the
There is a bug when you set the featured image on the top. This one has to be on the left or right. For alternative, use Elementor Extra.