The block has several parameters relating to responsiveness. You can set the size (in pixels) if the width of one image in the grid becomes less than this number, then the number of columns in the grid will be reduced by one.
Additionally, you can turn on rebuilding the grid in a single column on mobile phones or tablets.
The block above has a size of 6 X 2. The grid will be reduced by a certain number of columns so that the width of each of the posts is not less than 200px. On mobile phones, the grid will be rebuilt in one column.