Rmarkdown table latex has both greek and english words

I have this table with both greek and english words

   ---
output: 
  bookdown::pdf_document2:
  number_sections: true
  toc: yes
header-includes:
  - \usepackage{titling}
  - \usepackage{amssymb}
  - \usepackage{dcolumn} 
  - \usepackage[utf8]{inputenc}
  - \usepackage[english,greek]{babel}
  - \newcommand{\en}[1]{{\selectlanguage{english}#1}}
  - \newcommand{\gr}[1]{{\selectlanguage{greek}#1}}
  - \usepackage[useregional]{datetime2}
  - \usepackage{float}
  - \usepackage{colortbl}
---
---
title: \gr{ΤΕΣΤ}
subtitle: \en{TEST}
date: \today
---

```{r warning=FALSE, include=FALSE}
Sys.setlocale("LC_CTYPE","Greek")
```



```{r warning=FALSE, include=FALSE}
packages <- c("kableExtra")
if ( length(missing_pkgs <- setdiff(packages, rownames(installed.packages()))) > 0) {
  message("Installing missing package(s): ", paste(missing_pkgs, collapse = ", "))
  install.packages(missing_pkgs)
}
```
```{r message=FALSE, warning=FALSE, include=FALSE}
library(kableExtra)
```
  
  
```{r echo=FALSE,results='asis'}

x<-c("hello","hi","yellow","green","apple")
y<-c(rep(5,5))
r<-c(rep("καλημέρα",5))
data<-cbind(x,y,r)

kableExtra::kable(data, "latex", caption = "Πίνακας", booktabs = T, align = "c") %>%
  kable_styling(latex_options = "HOLD_position")

```

I fixed the yaml so as to use both languages in the text but in the table i cannot fix this The output that i have is

How can i make the english words to be appeared as the are in the right way? I want to be appeared both english and greek language on the table