Was the "three days and three nights" in the prophetic book of Jonah a complete span of 72 hours?

Question

Was the "three days and three nights" in the prophetic book of Jonah a complete span of 72 hours?

Is this "three days and three nights" to be taken literally or close to it or figuratively? Why or Why not?

What do the "reputable sources" (rabbis/sages of old) say?

Yonah - Jonah - Chapter 2:

1 And the Lord appointed a huge fish to swallow up Jonah, and Jonah was in the belly of the fish for three days and three nights.

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My question in relation to the three days and three nights is inspired from the previous question and answer Did Esther eat at the first feast she made for the king and Haman?, which give an indication that the quoted verse (in my above post) might not be interpreted at face value, if the "three days, day and night" in the Book of Esther (4:16) is a similar expression:

For example, "The Maharal in his commentary to Megillas Esther says that Esther only fasted for 70 hours (as opposed to 3 full days, 72 hours).... This is hinted in the verse "גַּם-אֲנִי וְנַעֲרֹתַי, אָצוּם כֵּן; וּבְכֵן אָבוֹא אֶל-הַמֶּלֶךְ" (Esther 4:17) "we will fast כן - "כן is Gematria 70 - Esther was saying that she would fast 70, and with those 70 hours she would come to the King."

Answer 1

The Da'at Mikra commentary (written by Elyakim Ben-Menachem) on this verse says that it means three full days (ie. 72 hours):

‮אִלו אמר שלשה ימים, לא היה במשמע שלשה ימים שלמים, אבל כשהוא אומר ימים ולילות, הרי ימים שלמים במשמע, כלומר: ששהה במעי הדג שלש יממות.

If it said "days", it wouldn't have implied three full days, but as it says "days" and "nights", it means full days, that is: he remained in the belly of the fish for 72 hours [lit. three 24-hour periods].

They don't source this explanation, but they do compare it to the description of Moses on Mt Sinai, where the verse (Exodus 24:18) says that he was there for 40 days and 40 nights; Ḥizkuni comments on this verse that that it was 40 full days (although he doesn't explicitly explain it from the "days" and "nights" language).

It says in Bereishit Rabbah 91:7 that God doesn't leave righteous people in dire straights for three days. Da'at Mikra adduces this and adds the words "(more than)", fitting with their explanation of a full 72 days. This could also be read without those words, and understood to be limiting Jonah's troubles to less than three full days.

On the other hand, there are those who take the whole book as fiction/allegory (eg Uriel Simon in his introduction to the JPS Bible Commentary), or the first two chapters as a dream/prophecy (eg some understandings of Rambam, ibn Caspi). In these approaches, the three days don't correspond to any explicit real-world time period. (Of course, the question could still be relevant for the proper explication of the dream/prophecy/allegory.)

Answer 2

Rabbeinu Bachaye (כד הקמח, כפורים, א, ב) writes that the three days and nights within the fish corresponded to the three days of the plague of darkness in Mitzrayim. I presume therefore that he understands them as three 24 hour periods.