News Home Page built with CSS Grid, Flexbox, and mobile-first workflow

I found it difficult to layout the desktop design. What could I have done better? I'm more familiar with Flexbox than with CSS Grid but decided to use it the layout the page instead of having to keep grouping elements into divs and then use Flexbox to align them. Should I have placed the bottom articles by themselves within the main container and used grid to position them instead. should I have not sectioned off so many elements into individual container and have used a 3x3 grid to layout everything? Would that have been one of if not the most effective and efficient method?