Cant change scale using TMAP and R shiny

Question

I have a database that looks like this: https://i.stack.imgur.com/SUQdw.png

and here are the files needed to execute this program: https://drive.google.com/file/d/1Vr5ae5At-OfwVp9LckfCyRPJAVp9IMoE/view

here is the map generated: https://vincentchangeon.shinyapps.io/carte/

here is the code

#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#
# Find out more about building applications with Shiny here:
#
#    http://shiny.rstudio.com/
#

library(dplyr)
library(sf) 
library(ggplot2)
library(tmap)  
library(leaflet)
library(stringi) 
library(tmaptools)
library(mapview) 
library(shiny)
library(rsconnect)


base= read.csv("bddlongsubstance.csv", stringsAsFactors = FALSE, encoding = "UTF-8", sep= ",", dec= ".",colClasses=c("code_postal_acheteur"="character"))
base= data.frame(base)
base$code_postal_acheteur= as.factor(base$code_postal_acheteur)
names(base)[1]= "ID"

codes_postaux= st_read(dsn = "codes_postaux_V5/codes_postaux_region.shp", 
                       layer = "codes_postaux_region",
                       quiet = TRUE) %>%
  select(ID, LIB, DEP)



codes_postaux$LIB= stri_encode(codes_postaux$LIB, from= "ISO-8859-1", to= "utf8")


fusion= codes_postaux %>% 
  left_join(base[1:19], by= "ID") %>%
  st_transform(2154)



fusion_vars <- setdiff(names(fusion), c("ID", "LIB", "DEP"))




ui <- fluidPage(
  tmapOutput("map"),
  selectInput("var", "Variable", fusion_vars)
)

server <- function(input, output, session) {
  output$map <- renderTmap({
    
    tm_basemap("CartoDB.Voyager")+ tm_shape(shp= fusion)+
      tm_borders("black", lwd= 0.3, alpha= 0.6)+
      tm_layout(title = "Quantité de substances phytopharmaceutiques achetées par année et par catégorie (en kilogrammes)", title.position = c("center", "bottom"), legend.bg.color = "white", legend.bg.alpha = 0.4)+
      tm_scale_bar(position = c("left", "bottom"))+
      tm_view(view.legend.position = c("right", "bottom"))
    
    
    
    
  })
  
  observe({
    var <- input$var
    tmapProxy("map", session, {
      tm_remove_layer(401) +
        tm_shape(fusion) +
        tm_polygons(var, zindex = 401)
    })
  })
}   


app <- shinyApp(ui, server)

the problem i face is that the scale in the map is meaningless, instead of 0 to 50 000, 50 000 to 100 000 ... I would like 0 to 100, 100 to 200, 200 to 400, 400 to 2000, 2000 to 4000, 4000 to 8000, 8000 to 6000.

I tried many times using tm_fill() but it never works, it doesnt generate an error but it just doesnt do anything.