In Australia we have a dearth of smart lock availability. I found one commercial solution, but at $2,500 it wasn't really an option.
After much research, I found the only option available - Schlage Sense lock/keypad and Schlage BR400 Sense Wi-Fi Adapter. I was advised by Schlage Australia that the adapter wouldn't work in Aus as the US used different frequencies, but I decided to try it anyway.
Those of you reading this outside Australia will be horrified at the costs we are saddled with here in Aus.
Schlage Sense lock & keypad (Amazon Australia) = A$314
Schlage BR400 Sense Wi-Fi Adapter (eBay) = A$180.
Total cost A$494!
But IT WORKS. I can remotely set a new key code for new guests and cancel it when they leave. I can lock & unlock the door from anywhere. Unfortunately, it doesn't have the functionality to set a code for a date interval; you can only set it for 24/7 or for a group of selected days of the week.
No relying on Airbnb sending a code a long time before guests arrive, I just send the code with my welcome message to them a short time before their arrival.