R plotly with custom colorbar

I am trying to reproduce a graph generated via ggplotly with plot_ly. I am struggling however with the colorbar.

This is the ggploty plot that I would like to reproduce, and in particular the colorbar:

library(plotly)

X <- data.frame(w = rep(c("a", "b"), each = 8),
                x = 1:16,
                y = 1:16,
                z = c(1, 1:13, 13, 13))

X$z_scaled <- (X$z-min(X$z))/(max(X$z)-min(X$z)) # scale to 0-1

# ggplot
gg <- ggplot(X) +
  geom_point(aes(x, y, color = z_scaled, alpha = w, text = paste0(x, ", ", y))) +
  scale_color_gradient2(low = '#0d71db', mid = "#dbc00d", high = '#db220d', 
                        midpoint = .5, breaks = 0:1, limits = 0:1) +
  scale_alpha_manual(name = " ", values = rep(1, nrow(X))) +
  labs(color = "Z", x = "", y = "")

ggplotly(gg, type = "scattergl", tooltip = "text") %>% toWebGL()

This is what I have with plot_ly:

length_unique_vals <- length(unique(X$z))
.colors <- colorRampPalette(c('#0d71db', "#dbc00d", "#db220d"))(length_unique_vals)
.colors <- .colors[factor(X$z)]

plot_ly() %>%  
  add_markers(
    data = X, x = ~x, y = ~y,
    split = ~w,
    text = ~paste0(x, ", ", y),
    hoverinfo = "text",
    type = "scattergl",
    mode = "markers",
    marker = list(
      # color = ~z_scaled,
      color = .colors,
      # colorscale = list(c(0, .5, 1), c("#0d71db", "#dbc00d", "#db220d")),
      colorscale = .colors,
      hoverlabel = list(bgcolor = .colors),
      colorbar = list(
        title = list(text = "Z"),
        len = .5,
        x = 1,
        y = .7
      )
    )
  ) %>% 
  layout(
    legend = list(x = 1, y = .4, bgcolor = 'rgba(255,255,255,0.6)')
  ) %>% toWebGL() %>% partial_bundle(local = FALSE)

As you can see, the colorbar is not displaying correctly. I have tried multiple possibilities (commented above) without success. What am I missing?

Edit
@Kat's answer solves the colorbar issue. However, if you want to use scattergl or toWebGl you will need to fix the hoverlabel background so it remains dynamic. Here is a solution for that below building on her answer.

length_unique_vals <- length(unique(X$z))
.colors <- colorRampPalette(c('#0d71db', "#dbc00d", "#db220d"))(length_unique_vals)
.colors <- .colors[factor(X$z)]

plot_ly() %>%
  add_trace(x = ~x, 
            y = ~y, 
            split = ~w,          # instead of alpha or opacity
            data = X,
            type = "scattergl",
            mode = "markers",
            color = ~z_scaled,   # color = var and colors = literal colors
            colors = c('#0d71db', "#dbc00d", '#db220d'),
            hoverlabel = list(bgcolor = .colors)) %>% # Fix hovercolor bg
  layout(xaxis = list(title = "",
                      dtick = 4,
                      zeroline = F,
                      gridcolor = "white"), # white on gray
         yaxis = list(title = "",
                      dtick = 4, 
                      zeroline = F,
                      gridcolor = "white"), # white on gray
         plot_bgcolor = "#eeeeee") %>%      # gray background
  colorbar(title = "Z",                     # colorbar title
           dtick = c(0, 1),                 # colorbar ticks
           thickness = 25) %>%              # width
           toWebGL() %>% partial_bundle(local = FALSE)

Edit 2
The hoverlabel bgcolor breaks down then the split factor is not ordered. This is why it needs to be ordered first.

library(plotly)
library(data.table)

X <- data.table(w = rep(c("a", "b"), 8), #not ordered
                x = 1:16,
                y = 1:16,
                z = c(1, 1:13, 13, 13))

X[, z_scaled := (X$z-min(X$z))/(max(X$z)-min(X$z))] # scale to 0-1

# Get colors for hoverlabel bgcolor
X <- X[order(w)]
length_unique_vals <- length(unique(X$z))
.colors <- colorRampPalette(c('#0d71db', "#dbc00d", "#db220d"))(length_unique_vals)
.colors <- .colors[factor(X$z)]

plot_ly() %>%
  add_trace(x = ~x, 
            y = ~y, 
            split = ~w,          # instead of alpha or opacity
            data = X,
            type = "scattergl",
            mode = "markers",
            color = ~z_scaled,   # color = var and colors = literal colors
            colors = c('#0d71db', "#dbc00d", '#db220d'),
            hoverlabel = list(bgcolor = .colors),
            marker = list(size = 10)) %>% # Fix hovercolor bg
  layout(xaxis = list(title = "",
                      dtick = 4,
                      zeroline = F,
                      gridcolor = "white"), # white on gray
         yaxis = list(title = "",
                      dtick = 4, 
                      zeroline = F,
                      gridcolor = "white"), # white on gray
         plot_bgcolor = "#eeeeee") %>%      # gray background
  colorbar(title = "Z",                     # colorbar title
           dtick = c(0, 1),                 # colorbar ticks
           thickness = 25) %>%              # width
           toWebGL() %>% partial_bundle(local = FALSE)