Hello,
Point is that product title has a different number of lines (from 1 to 3). To may try to set the fixed min-height for the product title in child theme style.css but then you will get a small gap for products with 1 line of the title. But if this is ok then you can try this solution
.content-product .product-title {
line-height: 2.5ex;
min-height: 5ex;
}
Regards