Cannot mainpulate time values based on HH:mm:ss format

[GhettoBurger996]

I have values like time values like so 08:00:00 and 22:00:00, following ISO 8601 standards and how postgres accepts "time" types.

The issue is I cant find a means of manipulating values like so using dayjs. For instance I cant get the difference between 2 time values using the format. The code block below return NaN, when attempting to format the time is return invalid date as well.

      const operationalHours: number = dayjs("22:00:00").diff(
        "08:00:00",
        "hour",
      );

      const format = dayjs("22:00:00").format("HH:mm:ss");

I cant change how the time is set, is their a workaround for this?