See Hours for Different Calendars
Simon Burbidge
Hi Katie. Thanks for your message, this is an interesting idea and I'll put it to the team. In the meantime, I felt like a challenge this morning, and made you a Shortcut that should do what you're after: https://www.icloud.com/shortcuts/91c10c4c441947e09a6b70e54712ec08
Just save the Shortcut to your phone (or iPad/Mac), and it will total up all the hours scheduled for each of your calendars for the current week - excluding All-Day events.
The shortcut itself is much more complicated than I thought it would be, but you can just hit the play button, or even just use Siri to run it for you. Anyway, thanks again for the suggestion, and I hope this helps.