As I said in my comment, if 2-1-3 / 4-1-5 instead of the desired 2-1-4 / 3-1-5 is also OK for placement, you can do this quite easily with CSS grid. MDN has a lot of resources about this topic.
Check out this fiddle, where I changed a MDN example a bit to your use case. The magic is here:
.wrapper > #first {
grid-row-start: 1;
grid-column-start: 2;
grid-row-end: span 2;
}
grid-row-start and grid-column-start places the element on the grid (and auto places all other elements to fill the remaining space). Then grid-row-end: span 2 tells CSS to make the element span 2 rows.