Thanks to ChatGPT 5 Pro. It took a long time to answer, but he answered correctly. I'm happy with the table. The best package I have tried so far for cross-tabulation. I think I'll be using the expss package for all my tables.

expss Authors need to prepare better support documentation. It's quite complicated and hard to find anything.

I am giving the solution for those who have the same problem.

library(expss) # load package
expss_output_viewer() # to view in the Viewer
mtcars %>%
  tab_cols(list("Miles/(US) gallon")) %>% # column names
  tab_cells(set_var_lab(mpg, "")) %>% # <-- Changed
  tab_rows(cyl) %>%
  tab_subtotal_rows("Total" = lo %thru% hi, 
                    position = "bottom") %>% # <-- changed
  tab_stat_fun("n" = w_n,
               "Mean" = w_mean,
               "Std. Err." = w_se,
               "Min" = w_min,
               "Max" = w_max,
               unsafe = FALSE,
               method = list) %>%
  tab_pivot()