Scientific formats for a table that has both very large and very small numbers

I want to display the large numbers in scientific format and keep the regular format for the small numbers to reduce column width. The real data have more columns than what is shown here.

dput(A)
structure(list(st2_1 = c(1437.21, 1019.03, 1199.3, 850.35, 67.32, 
586.62), st1_2 = c(0.12, 0.08, 855.64, 606.68, 687.06, 5987.41
), st2_2 = c(0.11, 0.08, 837.72, 593.98, 3659.78, 31893.5), `1-sum(e)` = c(1522.79, 
1075.11, 2092.52, 1513.48, 1052.3, 9066.99), sss_1 = c(0.05, 
0.03, 0.99, 0.7, 0.03, 0.29), sss_2 = c(0.02, 0.02, 0.43, 0.3, 
0.02, 0.19), f_1 = c(4099185668.8, 2766736655.89, 2093885714.17, 
1228712929.01, 5592860407.22, 560845021.29), f_2 = c(990125323.33, 
668282982.85, 14238156533.71, 8355091636.51, 10241029160.69, 
1026957549.35), f_3 = c(237420871.69, 160246712.8, 711346410.36, 
417425137.15, 6553794288.93, 657206264.75)), row.names = c(NA, 
6L), class = "data.frame")

The code below, provided at Flextable format column to scientific notation, doesn't work for me.

A %>%
flextable::flextable() %>%
     set_formatter(numbers = function(x) {
         formatC(x, format = "e", digits = 2)
     }) 

Here is another option: Using format() function with scientific and digits argument:

library(flextable)
library(dplyr)

A %>% 
  mutate(across(everything(), ~
                  case_when(. < 10000 ~ format(., scientific = FALSE),
                            . >= 10000 ~ format(., scientific = TRUE, digits = 2)))) %>% 
  flextable()