Certainly during the time bottas was at merc I would expect Hamilton to have at least 13 victories, he was always a number 2 driver that gave up positions and races for him.
That would be great if the Mercedes of 2017, 2018 and 2019 were the absolute class of the field. They weren't - Ferrari were faster in 2017 and 2018. And Ferrari had the fastest car for roughly 2/5ths of the season in 2019. Bottas was also allowed to win races for the first half of the year until Mercedes had to choose a driver to back for the WDC.