Hold on to your apps, this one is gonna get a little weird.
The default calendar view doesn’t provide a way to pick a timeslot when opening the form.
I came up with a hack using a new table that contains only one sheet column for the hour, and 7 virtual columns for the day of the week.
From there, I have a table view that shows related events to every Hour, pulling only events from This Week (Slice).
Then, I created 7 Edit actions, 7 Add actions, and 7 group actions and linked them to 7 more virtual columns!
Here’s the result: