header setting is :  logo left – menu right – with one widget.

Best is  ava_after_main_menu so widget is sibling to logo and nav container.

a lot of css rules are only needed because on this installation i had on default a shrinking header. This seems to be very difficult to obtain on your responsive settings you need.

For Info see: https://css-tricks.com/snippets/css/complete-guide-grid/

function enfold_customization_header_widget_area() {
	if(is_page(46036)){
	  dynamic_sidebar( 'grid-header' );
	}
}
add_action( 'ava_after_main_menu', 'enfold_customization_header_widget_area' );
.responsive #top.page-id-46036  .av-main-nav  #menu-item-search,
.responsive #top.page-id-46036  .av-main-nav #menu-item-search-desktop {
  display: none !important;
}

#top.page-id-46036 #header .container {
  height: 200px !important;
}
.html_header_top #top #main {
  padding-top: 200px !important;
}

/*** name the Grid Areas ***/
#header .logo { grid-area: feld1; justify-self: center;}
#header .main_menu { grid-area: feld2; justify-self: right }
#header .widget { grid-area: feld3; line-height: 1.5em; padding: 0 !important }


#header .inner-container {
  display: grid !important;
  margin: 0;
  gap: 30px;  
  grid-auto-flow: row;
  grid-template-columns: 1fr 1.5fr 1fr; 
  grid-template-areas:
    "feld3 feld1 feld2";
  justify-content:  space-between
}

#header .inner-container > * {
  align-self: center;
  width: auto !important;
  position: relative;
}

#header .widget p { margin: 0; }

#top.page-id-46036 #header #avia-menu {
  display: grid;
}

@media only screen and (min-width: 990px) {
  #top.page-id-46036 #header .avia-menu {
    top: 50%;
    transform: translateY(-50%)
  }
}

@media only screen and (min-width: 768px) and (max-width: 989px) {
  #top.page-id-46036 #header .avia-menu {
    height: 100% !important;
  }
}

#top.page-id-46036 #header #avia-menu li a {
  line-height: 40px !important;
  height: auto !important;
  float: right
}

#header .inner-container .logo a,
#header .inner-container .logo img {
  height: 190px !important;
  max-height: 190px !important;
  width: auto;
}


@media only screen and (max-width: 989px) {
  #header .inner-container {
    gap: 10px 0px;
    grid-template-columns: 3fr 1fr;
    grid-template-rows: 1fr 3fr;
    grid-template-areas: 
      "feld3 feld2"
      "feld1 feld1"
      ;
  }
  
  #top.page-id-46036 #header #avia-menu {
    height: 100%;
  }

  #top.page-id-46036 #header .container {
    height: 320px !important;
  }
  
  .responsive.html_mobile_menu_tablet.html_header_top #top #main {
    padding-top: 320px !important;
  }
  
  #header .inner-container .logo a, #header .inner-container .logo img {
    height: 200px !important;
    max-height: 200px !important;
    width: auto;
  }
}

#top #avia-menu > li.dropdown_ul_available > ul.sub-menu {
  position: absolute;
  left: -250px;
  top: 10px;
  background-color: rgba(230,230,230,0.5);
  border: 1px solid rgb(200,200,200) !important;
}



/* =============================================================== */
/* ====== if you change the values a little - you can have an overlapping logo ====== */
/* =============================================================== */
#top #header .logo {
  overflow: visible;
}

#header .inner-container .logo a, 
#header .inner-container .logo img {
  height: 250px !important;
  width: auto;
  max-height: 250px !important;
  overflow: visible !important;
}

#header .inner-container .logo img {
  padding: 10px
}

@media only screen and (max-width: 989px) {
  #header .inner-container .logo a, 
  #header .inner-container .logo img {
    height: 270px !important;
    width: auto;
    max-height: 270px !important;
  }
}