Multiple functions with names

df |> summarize(across(a:c, 
    list(mean = mean, median = median)
))

## # A tibble: 1 × 6
##   a_mean a_median b_mean b_median c_mean c_median
##    <dbl>    <dbl>  <dbl>    <dbl>  <dbl>    <dbl>
## 1 -0.111   -0.261  0.191  -0.0207  0.275    0.387