You can do this by adding some CSS to a child theme’s stylesheet or using a custom styles plugin (including, for example, the custom css module of jetpack)
You can override the js that sets the non-active panels to be visible in a media query targetting the tabs in accordion view, also
adding rules to change the appearance so it no longer has the appeartance of an accordion interface:
eg:
@media (max-width: 768px) {
.responsive-tabs .responsive-tabs__heading,
.responsive-tabs .responsive-tabs__heading:hover {
background: none!important;
border: 0!important;
color: #777!important;
cursor: default!important;
font-weight: 700!important;
}
.responsive-tabs .responsive-tabs__heading:after {
display: none!important;
}
.responsive-tabs .responsive-tabs__panel {
display: block!important;
border: 0!important;
}
}