How to make part of facet titles bold with a line break when pasting 2 variables together for title?

I want to mutate a column that has formatted facet titles that I can then use in a ggplot with facet_wrap. I know that I need to use plotmath and maybe bquote, but I am unable to get all of the components working together to produce the desired output. I have tried a lot of combinations of bquote and atop, as well as using ~ and .() and pasting things together, but no luck. I know that you can also use grob, but the output is in a knitted .Rmd. I also would like to make the top title larger if possible.

Reproducible Example

library(ggplot2)
library(dplyr)

mpg_df <- mpg %>%
  select(year, manufacturer, model, cty, hwy) %>%
  filter(
    year == 1999 & manufacturer == "audi" & model == "a4 quattro" |
      year == 2008 &
      manufacturer == "dodge" & model == "ram 1500 pickup 4wd"
  ) %>%
  mutate(
    title = paste0(
      "bold('This is the manufacturer ",
      manufacturer,
      "')~\n'This is the model ",
      model,
      "'"
    )
  )

mpg_df %>%
  ggplot(aes(x = cty, y = hwy)) +
  geom_point() +
  facet_wrap( ~ title, labeller = label_parsed) +
  theme_classic()

But they end up on the same line, and I'm not sure how to work atop into this, since \n does not work with plotmath.

I tried many other things for mutate with no luck, such as:

mutate(title = bquote(
          "atop(bold(This~is~the~manufacturer.(manufacturer)),
                This~is~the~model.(national))")

Expected Output

Using ggtext you could do add in markdown or html syntax to fit your needs

library(ggplot2)
library(ggtext)
suppressPackageStartupMessages(library(dplyr))

mpg_df <- mpg %>%
  select(year, manufacturer, model, cty, hwy) %>%
  filter(
    year == 1999 & manufacturer == "audi" & model == "a4 quattro" |
      year == 2008 &
      manufacturer == "dodge" & model == "ram 1500 pickup 4wd"
  ) %>%
  mutate(
    title = paste0(
      "**This is the manufacturer ",
      manufacturer,"**",
      " <br>This is the model ",
      model
    )
  )

mpg_df %>%
    ggplot(aes(x = cty, y = hwy)) +
    geom_point() +
    facet_wrap(vars(title)) +
    theme_classic() +
  theme(strip.text = element_markdown())

^{Created on 2024-08-16 with reprex v2.1.1}