I opened this editor up for another bubble user recently. It has the ability to automatically add time slots to store in the D.B. and for setting up availability.
Its not polished as a template, but anybody willing to pick something apart to learn how it works and then put it back together again on their own is welcome to take a look through.
Make sure to pay attention to the element tree to see everything that is on the page…you’ll really need to spend some time to work it out.
There is also a thread on custom calendars which is where I got most of this stuff