Now about your question, does this solve your problem?
library(dplyr)
# Sample date vector
as_date <- c("2022-03-11 UTC", "2022-03-16 UTC", "2022-03-21 UTC",
"2022-03-26 UTC", "2022-04-05 UTC", "2022-04-10 UTC",
"2022-04-15 UTC", "2022-04-25 UTC", "2022-04-30 UTC",
"2022-05-10 UTC", "2022-05-15 UTC", "2022-05-20 UTC",
"2022-05-25 UTC")
# Relevant code
as.data.frame(as_date) %>%
transmute(start_date = as_date,
end_date = lead(start_date)) %>%
head(-1)
#> start_date end_date
#> 1 2022-03-11 UTC 2022-03-16 UTC
#> 2 2022-03-16 UTC 2022-03-21 UTC
#> 3 2022-03-21 UTC 2022-03-26 UTC
#> 4 2022-03-26 UTC 2022-04-05 UTC
#> 5 2022-04-05 UTC 2022-04-10 UTC
#> 6 2022-04-10 UTC 2022-04-15 UTC
#> 7 2022-04-15 UTC 2022-04-25 UTC
#> 8 2022-04-25 UTC 2022-04-30 UTC
#> 9 2022-04-30 UTC 2022-05-10 UTC
#> 10 2022-05-10 UTC 2022-05-15 UTC
#> 11 2022-05-15 UTC 2022-05-20 UTC
#> 12 2022-05-20 UTC 2022-05-25 UTC