Adding padding or a spacer to top of 1 column in a gallery

Site URL: https://primrose-perch-4j4p.squarespace.com/

Hi there,

For my portfolio site I have used a gallery in 2 columns. I only use 7 images that are all square format. 1 column has 4 images and the other has 3. I wish to offset the side that has 3 images by adding a spacer or padding to the top so it feels masonry. I attempted to build manually with images and spacers however the grid did not size how I wanted it to this way.

I would also love to make the column of 4 default to the left but for some reason on desktop it sits to the right?

Would love some help!

Many thanks

Red