r summarize_if with multiple conditions

One possibility could be:

df_finale %>%
 summarise_all(~ if(is.numeric(.)) mean(., na.rm = TRUE) else Mode(.))

  num str
1   4 toy

Or an option since dplyr 1.0.0:

df_finale %>%
 summarise(across(everything(), ~ if(is.numeric(.)) mean(., na.rm = TRUE) else Mode(.)))