Yea it’s complicated.
I was thinking this using the repeater template and the almComplete callback function.
// Repeater Template
<article class="item" data-item="<?php echo $alm_item; ?>" data-total="<?php echo $alm_found_posts; ?>">
<h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
<p>Currently viewing item #<?php echo $alm_item; ?> of <?php echo $alm_found_posts; ?></p>
</article>
// JavaScript
window.almComplete = function(alm){
var item = alm.listing.querySelector('.item:last-child');
var last = item.dataset.item;
var total = item.dataset.total;
console.log("Viewing" + last + " of " + total );
};
This is untested, but basically. It gets the last item in the ALM loop and read the variables.
You could append this to an element somewhere on your page.
Again, this is the best I could do for you as nothing is built in for this, just pages.