Hi, Claire/Jonah.
tribe_is_ajax_view_request( 'photo' ) exists — from /wp-content/plugins/the-events-calendar/src/functions/template-tags/general.php
Also, there is an internal feature ticket for us to update from Isotope JS to either its latest version (to get https://isotope.metafizzy.co/layout-modes/fitrows.html) or to scrap it and use Flexbox CSS instead.
Either way, that’s really what we want here, and I’ve added your two threads about it to the internal ticket.
Please let me know if you have any follow-up questions on this topic.