how about adding a column with searchable spanish (without accents):

library(tibble)
library(stringi)
library(gt)


# Add a column without accents
days_of_week <- days_of_week %>%
  mutate(spanish_searchable = stri_trans_general(spanish, "Latin-ASCII"))

days_of_week |> 
  gt() |> 
  opt_interactive(use_search = TRUE)