Firstly, your question mentions the REST API, but you don’t actually appear to be using the REST API. You’re using admin-ajax.php. It’s an important difference in the context of your question.
Secondly, get_field_objects() function is an ACF function that gets data about the ACF fields. Not the meta, the literal fields created by ACF. So you’ll get things like the field type, label, instructions etc. Not just the value.
If you want all post meta assigned to a post, then you should use get_post_meta() without specifying a key:
$post->meta = get_post_meta( $post->ID );
All that being said, for your use case you should really just use the REST API. You’ll just need to use register_post_meta() to add your desired meta keys to the response, as documented here:
$meta_args = array(
'type' => 'string',
'description' => 'A meta key associated with a string meta value.',
'single' => true,
'show_in_rest' => true,
);
register_post_meta( 'page', 'my_meta_key', $meta_args );