You want to edit alter the display or their plugin. It does not matter what ACF can do. The first thing you need to know is where and how to alter the other plugin to change the display and add your own content.
Once you know how to do that then using ACF is simple.
I tried looking at the documentation, but I didn’t find anything with my quick look. I don’t know anything about that plugin so I can’t help you. They have a list of hooks here https://docs.theeventscalendar.com/product/the-events-calendar/, this one looks like it might be what you want, but I can’t say for sure, you’d have to test it https://docs.theeventscalendar.com/reference/hooks/tribe_events_single_event_title_html/
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