Does this work for you? I don't have the packages to check it.
xlkabular <- function(DF, Mylinesep = "\\addlinespace", ...) knitr::kable(DF, escape = FALSE, booktabs = TRUE, xltabular = TRUE,
linesep = Mylinesep, ...) |>
kableExtra::kable_styling(latex_options = "repeat_header")
or this
xlkabular <- function(DF, linesep = "\\addlinespace", ...) knitr::kable(DF, escape = FALSE, booktabs = TRUE, xltabular = TRUE,
linesep = linesep, ...) |>
kableExtra::kable_styling(latex_options = "repeat_header")