Removing white space below footer, missing featured image, etc

this is my website

1)At the bottom of the page there is a lot of white space, and I want to remove it.
2)in the search page no image appears, and this happens also in another webite. The featured image option is not deactivated
3)Under each h3 title there is a dash, and I want to remove it.

How I can do all this?Thanks

Hello @salvatore,

Please create a separate topic for each of your questions in order to make it easier to help you.

Kind Regards, Roman.