Few adjustments to the theme

Good morning, I set up Vega theme on my site, but I need some adjustments.

1) I would like to have the same image on each page of my site. I just uploaded the image header (not the banner for each page), but as you can see from my website, it looks quite nice and centrated on the main page, but not on the other pages (where it looks no so tidy and quite big).
Then, how can I keep the image on the front page clear and not “dark”?

2) how can I delete the “Blog” sentence in the middle of my header image, when I open the blog page?

3) I reduced the measures of my logo, because on the mobile version the menu overlapped the whole logo and I didn’t like the effects. But now, as it’s too small, it looks like not so tidy. Is there anything I can do to upload a clear image of my logo at those measures?

4) At the very bottom of my site, on the light blue banner where you can read the Vega theme property, on the left there is also the menu of my site, reproducing the main pages I connected to the main menu. I am not interested in viewing the pages on that banner, how can I delete that part on my site?

Thanks for your support

The page I need help with: [log in to see the link]