I have not used either method so take this with a grain of salt.
I believe that the plugin ACF to REST API adds the custom endpoint mentioned /wp-json/acf/v3/options/options
WP is not likely to add an endpoint that relates specifically to ACF Options Pages.
I can find no mention of an endpoint for getting options using the WP Rest API, but this is what you are looking for. As far as I can tell this does not exist.
ACF options are store in the wp_options table, generally with the option_name of "option_{$field_name}" although this will be different if you specify a custom string as a post ID and will use that ID instead of “option”
