I'm honestly shocked that this isn't standard. This would go a long way with clients saying "I don't see any available this month"

This is a huge deterrent for clients. Especially when it’s the end of one month and bookings are intended to be 3 weeks out, for example. If there’s a holiday at the end of the next month, there may not be availability for 2 calendar months.

Example: the client goes to book at the end of April, but there’s no availability for 3 weeks. Then Memorial Day comes along. So they can’t technically book till June. they even go through the process of clicking through to find dates, something feels off about it to them.

Simply, the first month shown should be the first month that a booking is available.