Minimum breaks in breaks_extended ? (for example in a ggplot)

I was wondering if it actually exists a minimum breaks for breaks_extendend.

In my example, i have data with Year (= Annee) with 3 values 2021, 2020, 2019

df %>% 
  ggplot(aes(Mois, Annee)) + 
  geom_jitter() +
  xlab(x) +
  ggtitle("Nuage de points") +
  scale_x_continuous(breaks = breaks_extended(12)) +
  scale_y_continuous(breaks = breaks_extended(4)) +
  theme(plot.title = element_text(face = "bold", hjust = 0.5))

breaks_extended(3) display only one break (2020) but i would like 3.

breaks extended(4) work!

thanks in advance!