It's odd having to reply to something from 2019, especially something as relatively straightforward as this feature request should be, but here I am. If anything, I think it could easily be an option that can be checked in the dropdown menu to the right of the "today" button, to always open on the current time period selected (current day, week, month, etc).
I understand that this shouldn't be a forced feature for all, but an option to check off for those who need it would be great.