Explorer only accepts NaiveDateTime. The following should work:
datetime_series =
["2023-08-29T15:38:00", "2023-08-29T14:17:28", "2023-08-29T12:53:17"]
|> Enum.map(&NaiveDateTime.from_iso8601!/1)
|> S.from_list()
# #Explorer.Series<
# Polars[3]
# datetime[μs] [2023-08-29 15:38:00.000000, 2023-08-29 14:17:28.000000,
# 2023-08-29 12:53:17.000000]
# >
Then you should be able to compute the min/max no problem:
S.max(datetime_series)
# ~N[2023-08-29 15:38:00.000000]
S.min(datetime_series)
# ~N[2023-08-29 12:53:17.000000]
