Hello Susan,
Thanks for going Pro and welcome to the forums!
Great question you have there. I am able to answer some questions to help you get started on a customization for this, but for the most part that is beyond the support we can provide.
Here is a snippet that can help you get started. Paste it into your child theme’s functions.php file and that should do the trick. Note, if there is already code in that file, then likely you will not need the opening <?php tag.
https://gist.github.com/andrasguseo/552c25143f0856341166acc4c72c5436
This will change all your views to show only today’s events. If you only want that for your map view, then you will need to further customize the code.
Let me know if you have any follow up questions.
Cheers,
Andras