Create from multiple data frames complex customized figure on ggplot2

I am working on a project where I need to combine data from two different data frames into a single plot using ggplot2 in R. I was wondering how I can efficiently achieve this, assigning specific features to each dataset in the plot.

I have two data frames, each with different variables. I would like to overlay plots for df1 and df2 on a single graph while customizing plot features such as colors, shapes, and labels for each dataset.

I want my plot to feature two background ellipses, one in purple and the other in green, along with the centroid of each ellipse. These ellipses are generated using stat_ellipse and data from df2. In the foreground, I would like the points from df1 to be visible, but with a color gradient as specified in the following script:

# Create data frame df1
df1 <- data.frame(
  x = c(1, 2, 3, 4, 5),
  y = c(2, 4, 3, 6, 5),
  color = runif(5, 0, 1))


# Create data frame df2
df2 <- data.frame(
  x = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
  y = rnorm(10),
  group = rep(c('A', 'B'), each = 5))

To create the plot, I'm not sure whether the information should go directly into the 'ggplot()' code or, alternatively, into 'geom_point' and 'stat_ellipse'. Either way, I'm unsure how to adjust the colors separately for each component of the plot.

plotGG <- ggplot() +
  stat_ellipse(data = df2, aes(x = x, y = y, color = group)) + #i want those ellipses purple and green
  geom_point(data = df1, aes(x = x, y = y, color = color), size = 3) +
  scale_color_gradient2(midpoint=0.5,low="#ba1414ff",mid = "#f3f3b9ff",high="#369121ff") #this is the color pallete that i want for the geom_points

I have progressed to this point, but it generates errors one way or another. Thank you in advance!

In vanilla ggplot2 you can have only scale per aesthetic (whereas you want two different color scales) and either is this scale discrete or continuous (whereas you want a discrete and a continuous color scale).

But one option to a achieve your desired result would be the ggnewscale package which allows for multiple scales for the same aesthetic:

set.seed(123)

# Create data frame df1
df1 <- data.frame(
  x = c(1, 2, 3, 4, 5),
  y = c(2, 4, 3, 6, 5),
  color = runif(5, 0, 1)
)

# Create data frame df2
df2 <- data.frame(
  x = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
  y = rnorm(10),
  group = rep(c("A", "B"), each = 5)
)

library(ggplot2)
library(ggnewscale)

ggplot() +
  stat_ellipse(
    data = df2,
    aes(x = x, y = y, color = group)
  ) +
  scale_color_manual(
    values = c(A = "purple", B = "green")
  ) +
  ggnewscale::new_scale_color() +
  geom_point(
    data = df1,
    aes(x = x, y = y, color = color), size = 3
  ) +
  scale_color_gradient2(
    midpoint = 0.5,
    low = "#ba1414ff", mid = "#f3f3b9ff", high = "#369121ff"
  )