Highcharter R: Changing the "series" label for plots with multiple Y axis

Question

I have a data frame called raw data that looks like this:

head(rawdata)
# A tibble: 6 x 9
  Time                 Temp    DO Pump1 GasFlo    O2    pH  Agit Pump3
  <dttm>              <dbl> <dbl> <dbl>  <dbl> <dbl> <dbl> <dbl> <dbl>
1 2023-08-08 22:00:00    37  134.     0    4.9     0  6.75  1200     0
2 2023-08-08 22:00:00    37  136.     0    4.9     0  6.75  1200     0
3 2023-08-08 22:01:00    37  132      0    4.9     0  6.75  1200     0
4 2023-08-08 22:01:00    37  134      0    4.9     0  6.75  1200     0
5 2023-08-08 22:02:00    37  134.     0    4.9     0  6.75  1200     0
6 2023-08-08 22:02:00    37  136.     0    4.9     0  6.75  1201     0

I want to plot Time in the X axis and the rest of the variables in the Y axis, and I would like to replace the "Series 1" "Series 2" ... "Series n" labels that appear automatically below the X axis with the actual name of the variables and their respective colors.

I want to plot all variables but to make the code simpler I only included three of them in this example. Here's what I have so far:

  highchart() %>%
  hc_chart(type = "line") %>%
  hc_xAxis(categories = rawdata$Time) %>%
  hc_yAxis_multiples(create_axis(naxis = 3),
                     list(title = list(text = "pH"),
                          lineWidth = 3,
                          showLastLabel = TRUE,
                          opposite = FALSE),
                     list(title = list(text = "DO"),
                          lineWidth = 3,
                          showLastLabel = TRUE,
                          opposite = FALSE),
                     list(title = list(text = "Base"),
                          lineWidth = 3,
                          showLastLabel = TRUE,
                          opposite = FALSE)) %>%
  hc_add_series(rawdata$pH, yAxis = 0) %>%
  hc_add_series(rawdata$DO, yAxis = 1) %>%
  hc_add_series(rawdata$Pump1, yAxis = 2)  

it turns out like this: This is the plot I get after running this code

I went over the highcharter package documentation but I just can't find how to replace those "Series" labels with the actual name of the variables. I haven't used R in years so please be nice :)