How to align values of a column right in a data frame in r

Question

I was trying to take the mean of rows, but when I ran the below, it gave me an error.

thetable = thetable %>% 
  rowwise() %>% 
  mutate('2020rate'=mean(c_across(98:109)))

Error in `mutate()`:
! Problem while computing `2020rate = mean(c_across(98:109))`.
i The error occurred in row 1.
Caused by error in `stop_vctrs()`:
! Can't combine `Jan 2020` <double> and `Mar 2020` <character>.
Run `rlang::last_error()` to see where the error occurred.

I looked at the row in question, and it turns out that the entire column is left aligned, while the rest of the data is right aligned.

data frame:

Jan2020  Feb2020  Mar2020  Apr2020
      5        3  2              2
      3        4  5              3

I saw a method to use gt(), but this turns it into an unreadable data frame. Is there another way to align all column values right?