Hello,
Add extra class for buttons https://prnt.sc/3ohga9DEJzri
button-width-100
then add the next code in Theme Options > Theme custom CSS > Global:
.et-fancy-button.button-width-100 .button-wrap a {
padding-left: 0px;
padding-right: 0px;
}
.et-fancy-button.button-width-100 .button-wrap {
width: 100%;
}
Regards