Yeah that will work so your code would look like this:
.wp-block-post-template.is-flex-container li {
display: flex;
flex-direction: column;
}
.wp-block-post-template.is-flex-container li :last-child {
margin-top: auto;
}
.gb-container-eaa30a35 .wp-block-query ul.wp-block-post-template {
row-gap: 50px;
}