Split large dataframe into smaller dataframes based on file size

I have a large dataframe containing multiple variables (categorical and numerical), which I want to split into smaller ones such that each smaller file that I export (as CSV) is not larger than 1 MB. I would also like to do this in the tidy style, without looping.

Here's an example:

df <- data.frame(matrix(runif(42000*11), ncol = 11)) %>% 
  mutate(ID = rep(LETTERS, length.out = 42000)) %>% 
  arrange(ID)

write_csv(df, "df.csv") # 9.0 MB file

Here, I would ideally split df into 9 or 10 different files, each not more than 1MB. Also, since there are grouping variables like ID, the split should not happen in the middle of a group.

I came across split() and group_split() in other threads here on SO, but none of them mention splitting based on file size. I guess this will require a custom function? Or maybe there is some rows:filesize ratio that I can use to decide the maximum number of rows any smaller dataframe should have and proceed that way?