Thanks for reaching out!
As mentioned in our public Matrix space this feature would indeed be interesting! Can you describe how you'll expect it to behave? Should it interact with the calendar app?
For your information, we usually can't work on a feature if it isn't funded. Don't hesitate to subscribe to a premium plan on our CryptPad.fr instance and/or become a recurrent financial contributor on our OpenCollective page: https://opencollective.com/cryptpad