Using the flexbox version?
This version of the column-count one i provided should apply to ALL block galleries:
@media (min-width: 769px) {
.wp-block-gallery {
display: block !important;
column-count: 3;
}
}
@media (max-width: 768px) and (min-width: 420px) {
.wp-block-gallery {
display: block;
column-count: 2;
}
}