In the afternoon I took a photo of another sunflower flowering. This is the second one in our garden, the first one opened the 31st of August 2020.
In the above photo you can see the first one, which has finished flowering (top, center), and another one that's close to fully open (bottom, center). The plants grew from seeds dropped by birds. Most likely western jackdaw (Coloeus monedula) as they were very common in our garden when we fed seeds to the birds.