How do I group Xs in ggplot2?

Something like this?

1. Aggregate the data with summarise;
2. in the ggplot error bar and point layers, use position = position_dodge(width = 0.5).

In the example below I use the built-in data set mtcars.

library(ggplot2)
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union

mtcars %>%
  mutate(am = factor(am, labels = c("automatic", "manual"))) %>%
  summarise(
    mpg_min = min(mpg),
    mpg_max = max(mpg),
    mpg = mean(mpg),
    .by = c(cyl, am)
  ) %>% 
  ggplot(aes(cyl, mpg, color = am)) +
  geom_errorbar(aes(ymin = mpg_min, ymax = mpg_max),
                position = position_dodge(width = 0.5),
                width = 0.25) +
  geom_point(position = position_dodge(width = 0.5)) +
  scale_color_manual(values = c(automatic = "orange", manual = "green")) +
  theme_bw()

^{Created on 2024-10-07 with reprex v2.1.0}