With R and ggplot2, you have to pivot to long format for plotting.
library(tidyverse)
df %>%
pivot_longer(-c(Date, Item), names_to = "time", values_to = "value") %>%
mutate(time = ymd_hm(paste("0000-01-01",time, sep = " "))) %>%
ggplot(aes(x = time, y = value)) +
geom_line(aes(colour = Date)) +
scale_x_datetime( breaks=date_breaks("60 min"), labels = date_format("%H:%M")) +
theme(axis.text.x=element_text(size=8, angle = 90),
axis.text.y=element_text(size=8),
axis.title=element_text(size=10)) +
facet_grid(~Item, scale='free_x')

Another option if you want both series on the same plot.
library(tidyverse)
df %>%
pivot_longer(-c(Date, Item), names_to = "time", values_to = "value") %>%
mutate(Date = as.Date(Date, "%m/%d/%Y")) %>%
mutate(time = as.POSIXct(paste(ok$Date, ok$time), format="%Y-%m-%d %H:%M")) %>%
ggplot(aes(x = time, y = value, colour = Item, group = Item)) +
geom_line()
*Note: Since it is just a sample of the data, there are time gaps, hence the sharp angles.

Or if you want them separate, then you can facet the plot (also using bar for another alternative).
df %>%
pivot_longer(-c(Date, Item), names_to = "time", values_to = "value") %>%
mutate(Date = as.Date(Date, "%m/%d/%Y")) %>%
mutate(time = as.POSIXct(paste(ok$Date, ok$time), format="%Y-%m-%d %H:%M")) %>%
ggplot(aes(x = time, y = value)) +
geom_bar(stat = "identity", aes(colour = Item, fill = Item)) +
facet_grid(~Item, scale='free_x')

Data
df <- structure(list(Date = c("1/1/2022", "1/2/2022", "1/3/2022", "1/4/2022",
"1/1/2022", "1/2/2022", "1/3/2022", "1/4/2022"), Item = c("foo",
"foo", "foo", "foo", "bar", "bar", "bar", "bar"), `0:00` = c(2,
1.5, 1, 2, 3, 2.5, 1, 2), `1:00` = c(3L, 1L, 2L, 1L, 1L, 4L,
2L, 1L), `2:00` = c(4L, 3L, 3L, 3L, 0L, 3L, 1L, 3L), `3:00` = c(1,
2, 1, 4, 1.5, 1, 1, 2), `4:00` = c(5, 2.5, 2, 1, 5, 2.5, 2, 1
), `5:00` = c(1.5, 6, 5, 2.4, 1.5, 0, 1.5, 2.5), `6:00` = c(2.5,
4, 4, 3, 2.5, 1, 4, 3)), class = "data.frame", row.names = c(NA,
-8L))