In which ambient temperature is it best to place the wine cooler?

This depends on the climate class of the cabinet (found on the type plate inside the cabinet or on the back)

Climate class / Permitted room temperature

SN: +10 °C to+32 °C
N: +16 °C to +32 °C
ST: +18 °C to +38 °C
T: +18 °C to +43 °