Plus now we can see that there is some work being done on the flower border, ooh, nice paving stones
and look at that rich soil. (I am so jealous.
I'm not a Dahlia grower myself. When I worked as a floral designer my boss grew his own Dahlia flowers to use in floral arrangements and he taught us quite a bit about how to grow Dahlias. I don't know your location/zone but here is a link for a video that may help you when the weather gets colder.
If you live in a warmer climate you may be able to leave the tubers in the ground (with proper care and mulching) but the tubers will still need to be divided every few years.
Good luck with the Dahlia and keep the photos coming!