Equal Heights for Buttons in Columns

Hi there
I have used an advanced column to add three columns each with HTML (from Amazon to generate an image) with a UAG multi button buy now button underneath, also in the column. I have tried to adapt this CSS but cannot work out which class to use to get it to work, any help is appreciated.

.wp-block-column {
display: flex;
flex-direction: column;
}

.wp-block-column .wp-block-buttons {
margin-top: auto;
}`