library(tidyverse)
library(lubridate)
rm(list=ls())
tibble(date = seq(as.Date('2023-03-01'), as.Date('2023-03-31'), 'days')) %>%
  # manually setting the weekday using factor with the order of weekdays,
  # make monday first in levels if so desired. Use abbreviations if 
  # desired, but also you'll need to rename the levels
 mutate(wkdy = factor(weekdays(date, abbreviate=T), levels=c('Sun','Mon','Tue','Wed','Thu','Fri','Sat')), 
         wkn = week(date), 
         mo = month(date, label=T, abbr=F),
         day = day(date)) %>%
  # the group_by and dense rank creates
  # a column which represents week of the month
 group_by(mo) %>% 
  mutate(wkn.mo = dense_rank(wkn)) %>%
  ungroup() %>%
  # basically each calendar day is ploted as a geom tile
  # the weekday number and week month number define the location
  ggplot(aes(x=wkdy, y=wkn.mo)) +
  # you can use aesthetics to colorize the tiles
  geom_tile(alpha=0.8, fill='gray', width=0.9, height=0.9) + 
  # use additional geom text to add text of different sizes
  geom_text(aes(label=day), size=20, hjust=0.5) +
  # for multiple months you will want to use facet_wrap
  # set for each month. Scales = "free" ensures the 
  # day of week labels are repeated for each month's calendar
 # but if you use scales = "free" below you have to switch the 
 # coord_fixed to coord_cartersian which will make the grids on the 
 # calendar non-square.
  #   facet_wrap(~mo) +
  # puts the day of week labels up top
  scale_x_discrete(position = "top") +
  # remove any default theme position
  theme_void() +
  # This reverses the axis and adds margin. Need to
  # change for months with six weeks like April 2023 to
  # c(6.6, 0.4). You could also use scale_y_reverse but
  # I'd rather set manual limits so all months have the
  # same height when using facet wrap
  coord_fixed(expand=F, ylim=c(5.6, 0.4)) + 
  # set labels
  labs(title="March 2023", 
       x="", y=""
  ) +
  theme(
    plot.background = element_rect(fill='white', color='white'),
    # strip.placement outside puts month name above the x axis 
    # date lables
    strip.placement = 'outside',
    text = element_text(family = 'Arial', size=40),
    plot.title = element_text(face='bold', size=60, hjust=0.5, margin=margin(0,0,10,0)),
    axis.text.x = element_text(size=20),
    plot.margin = margin(30,30,30,30),
    legend.position = 'none'
  )