If each of your Widget areas are to only contain 1 widget then you can just stack all widgets in one Widget area, set the Layout to only display one and then use some CSS Grid like this:
.footer-widget-1 {
display: -ms-grid;
display: grid;
-ms-grid-columns: (1fr)[6];
grid-template-columns: repeat(6, 1fr);
-ms-grid-rows: 1fr 1fr;
grid-template-rows: 1fr 1fr;
}
.footer-widget-1:before {
display: none;
}
.footer-widget-1 aside:first-child {
-ms-grid-column-span: 2;
grid-column: span 2;
-ms-grid-row-span: 2;
grid-row: span 2;
}
Note: The Customizer > Additional CSS will throw errors at this code, you can just ignore them and check the warning box to save.
If that works for you then i can assist with the tablet / mobile layout. An image of that would be handy.