Reply To: Blocks per row (front) page mobile version

I can’t be sure from your image, but are you using the standard “Columns” block?

If so, add this CSS to ‘Appearance’ > ‘Customize’ > ‘Additional CSS’:

@media (max-width:599px) {
    .wp-block-column {
        flex-basis: calc(50% - 16px) !important;
        flex-grow: 0;
    }
    .wp-block-column:nth-child(2n) {
        margin-left: 32px;
    }
}