CSS: How to wrap rows in wkhtmltopdf

Question

I'm on Drupal 9 and with the entity-print module trying to get images to wrap after 2 images, in other the rows break into next line.

Does that work in pdf?

Use case: users add 6 images, but would like to display 2 in a row, so 50% each.

• Image 1, 2
• Image 3, 4
• Image 5, 6

With the css below, they resize and display as 1,2,3,4,5,6 next to each other

    display: -webkit-box; /* wkhtmltopdf uses this one */
    display: flex;
    -webkit-box-pack: center; /* wkhtmltopdf uses this one */
    justify-content: center;
    flex-wrap: wrap;
}

.row > div {
    margin: 5px;
    -webkit-box-flex: 1;
    -webkit-flex: 1;
    flex: 1;
}

.row > div:last-child {
    margin-right: 0;
}

Most appreciate any guidance.