Can you please help me to get rid of the lines at (1) and remove the blank space

Hey diefleischerei,
Thanks for the screenshot and link, Please try this code in the General Styling > Quick CSS field or in the WordPress > Customize > Additional CSS field:

#top.home .main_color .avia-content-slider .slide-image {
	background: transparent !important; 
}
#top.home .avia-smallarrow-slider-heading.no-logo-slider-heading {
	display: none !important;
}
#top.home #text > div > div {
	padding-top: 0px !important;
}
#top.home #av_section_1 > div > div > div > div > div {
	margin-top: 0px !important;
}

After applying the css, Please clear your browser cache and check.

Best regards,
Mike