Hi @Penny441
Unfortunately, Airbnb removed the ability to block dates outside your availability window in the Summer 2023 Release on the regular calendar. The only way to do that now is to turn on Pro Tools and use the multicalendar to manually block dates outside your default availability window. All hosts can use Pro Tools now (the help articles still say you need more than 6 listings but that is incorrect). Here is a Guide on how to turn on Pro Tools and use the multicalendar:
Use Pro Tools & The Multicalendar
https://community.withairbnb.com/t5/Community-Guides/GUIDE-Use-Pro-Tools-to-Set-Calendar-Custom-Pric...
Once you turn on Pro Tools, go to the multicalendar, select the dates you want to block and choose "blocked". It will look like this: