Hi. To be clear, there is no /wp-content/plugins/events-calendar-pro/src/views/pro/single-event.php file so there wouldn’t be an override at [your-theme]/tribe-events/pro/single-event.php — it is only to be overridden at [your-theme]/tribe-events/single-event.php (reference: Themer’s Guide)
However, if your theme already customizes this file, overriding their customizations via a child theme would need to be answered by their support.
It seems you linked to their solution, but I cannot view all of it because I’m not logged into their forums — and there was quite a bit of back-and-forth so I’m unsure exactly what you were trying to reference from their forum.
Please let me know if you have any follow-up questions on this topic.