If there is nothing better, I propose something like this, for a start:
add_action('admin_head', 'hb_acf_custom_fonts');
function hb_acf_custom_fonts() {
echo ' <style>
.acf-block-body.is-edit {
font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif !important;
}
</style>';
}