Hi Michael,
Thanks so much for reaching out!
Just to let you know, we are limited by our Support Policy in how much we can help with customizations, but I will try to point you in the right direction.
I’d recommend starting off by taking a look at our Themer’s Guide, which can show you which templates can be edited and copied in order to achieve the results that you are looking for.
You’ll want to take a look at the the-events-calendar/src/views/functions/template-tags/ ical.php file.
Let me know how that goes!
Thanks,
Jaime