How to join points using lines and spacing text ticks in the x axis in ggplot?

I have the following data on jeans and I want it to plot it in the most understandable way focusing on the sizes available.

jeans <-  tribble(~ category, ~ brand, ~size_value,
"Jeans","BE GANESHA","38",
"Jeans","BE GANESHA","40",
"Jeans","BE GANESHA","42",
"Jeans","BE GANESHA","44",
"Jeans","BE GANESHA","34",
"Jeans","BE GANESHA","36",
"Jeans","Bendita Be","M",
"Jeans","Bendita Be","XL",
"Jeans","By Florencia","0",
"Jeans","By Florencia","1",
"Jeans","By Florencia","2",
"Jeans","By Florencia","3",
"Jeans","CLARA AGUAYO","U",
"Jeans","Caro Criado","L",
"Jeans","Caro Criado","M",
"Jeans","Caro Criado","XS",
"Jeans","Caro Criado","S",
"Jeans","Caro Criado","XL",
"Jeans","Joséphine","32",
"Jeans","Joséphine","34",
"Jeans","Joséphine","36",
"Jeans","Joséphine","38",
"Jeans","Joséphine","40",
"Jeans","LAS MARCAS","L",
"Jeans","LAS MARCAS","M",
"Jeans","LAS MARCAS","S",
"Jeans","LAS MARCAS","XL",
"Jeans","LAS MARCAS","XS",
"Jeans","LAS MARCAS","XXL",
"Jeans","LIMITE","1",
"Jeans","LIMITE","2",
"Jeans","LIMITE","3",
"Jeans","LIMITE","4",
"Jeans","LIMITE","5",
"Jeans","LIMITE","6",
"Jeans","LIMITE","0",
"Jeans","MARIMBA MULTIMARCAS","31",
"Jeans","MUTMA","26",
"Jeans","MUTMA","27",
"Jeans","MUTMA","28",
"Jeans","MUTMA","29",
"Jeans","MUTMA","30",
"Jeans","MUTMA","31",
"Jeans","Margara Shaw","L",
"Jeans","Margara Shaw","M",
"Jeans","Margara Shaw","S",
"Jeans","Margara Shaw","XL",
"Jeans","Margara Shaw","XS",
"Jeans","Margara Shaw","XXL",
"Jeans","Margara Shaw","4XL")

jeans_pants %>% 
    mutate(size_value = case_when(
              size_value == "S/M" ~ "S/M ", 
              size_value == "M/L" ~ "M/L ", 
              size_value == "L/XL" ~ "L/XL ",
              size_value == "S/M" ~ "S/M ", 
              size_value == "M/L" ~ "M/L ", 
              size_value == "L/XL" ~ "L/XL ",
              size_value == "XL" ~ "XL    ",
              size_value == "XXL" ~ "XXL    ",
              size_value == "XXXL" ~ "XXXL    ",
              .default = as.character(size_value)),
           size_value = factor(size_value, levels = c("U", "0", "1", "2", "3", "4", "5", 
                                                      "6",
                                                      "S/M ", "M/L ", "L/XL ",
                                                      "XXS", "XS", "S", "M", "L", "XL   ", 
                                                      "XXL    ", "XXXL    ", "4XL",
                                                      "22", "23", "24", "25", "26", "27", 
                                                      "28", "29", "30", "31", "32", "33", 
                                                      "34", "36", "38", "40", "42", 
                                                      "44"))) %>% 
    arrange(brand, desc(size_value)) %>% 
    ggplot(aes(size_value, brand)) +
    geom_point(aes(color = size_value), alpha = .6, size = 3) +
    scale_color_manual(values = rep(c("#8E6151", "#988880"), 38)) + 
    theme(legend.position = "none",
          panel.border = element_blank(),
          panel.grid.minor.x = element_blank(),
          axis.text.x = element_text(margin = margin(r = 22))))

In the first place, I want to draw a line between the points of the same scale (I'm going to show a picture above of the desired outfit). And then, I tried manually to space in the axis XL, XXL, and XXXL but I can't.

I would really appreciate the help and any further suggestions on visualisation.

Here I left an example of a brand with multiple sizes' scales:

data <- tribble(~brand,~size_value,
"BE GANESHA","38",
"BE GANESHA","40",
"BE GANESHA","42",
"BE GANESHA","44",
"BE GANESHA","34",
"BE GANESHA","36",
"Margo Baridon","24",
"Margo Baridon","26",
"Margo Baridon","28",
"Margo Baridon","30",
"Margo Baridon","32",
"Margo Baridon","34",
"BE GANESHA","M",
"BE GANESHA","L",
"BE GANESHA","S",
"BE GANESHA","XL",
"BE GANESHA","XS",
"BE GANESHA","XXL",
"Margo Baridon","L",
"Margo Baridon","M",
"Margo Baridon","S",
"Margo Baridon","XS",
"Margo Baridon","24",
"Margo Baridon","26",
"Margo Baridon","28",
"Margo Baridon","30",
"Margo Baridon","32",
"Margo Baridon","34",
"Margo Baridon","XL")

I believe that ggplot2 does not support arbitrary spacing on a discrete axis (I'm curious to find solutions that do!). In the interim, let's shift to a continuous x-axis, predefining the corresponding x locations based on the desired widths. (This precludes the need to add spaces.)

sizes <- tibble(size_value = c("U", "0", "1", "2", "3", "4", "5", "6",
                               "S/M", "M/L", "L/XL",
                               "XXS", "XS", "S", "M", "L", "XL", 
                               "XXL", "XXXL", "4XL",
                               "22", "23", "24", "25", "26", "27", 
                               "28", "29", "30", "31", "32", "33", 
                               "34", "36", "38", "40", "42", "44"),
                x = lag(cumsum(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 4L, 4L, 5L, 3L, 2L, 1L, 1L, 
                             1L, 6L, 7L, 8L, 3L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
                             2L, 2L, 2L, 2L, 2L, 2L, 2L)), default=0)
)

(The order and widths were inferred from your previous code.)

We'll left_join this onto your jeans. Note that I am not guarding against any jeans$size_value not found in sizes$size_value; if that occurs, x= will be assigned NA and likely not plotted.

Since you wanted lines among points grouped by brand, I'll add that too (under the dots), though that's "just because". I also added theme_bw() to simplify the theme, more akin to what you had as a demo in the question.

jeans %>%
  left_join(sizes, by = "size_value") %>%
  mutate(size_value = factor(size_value, levels = sizes$size_value)) %>%
  arrange(brand, desc(size_value)) %>%
  ggplot(aes(x, brand)) +
  geom_line(aes(group = brand)) +
  geom_point(aes(color = size_value), alpha = .6, size = 3) +
  scale_color_manual(values = rep(c("#8E6151", "#988880"), nrow(sizes))) +
  scale_x_continuous(breaks = sizes$x, labels = sizes$size_value) +
  theme_bw() +
  theme(legend.position = "none",
        panel.border = element_blank(),
        panel.grid.minor.x = element_blank(),
        axis.text.x = element_text(margin = margin(r = 22)))