What you call Drash I call Pshat.
The story of Rivkah and her babies as well as everything in the Torah is literal, it is historical fact. Concurrent with this historical truth we must also understand that everything in the Torah is metaphoric. Acknowledging the deeper layers gives us a richer more complex appreciation for the Torah and its practical messages for the good life.
(23) And the LORD said to her: Two nations are in your womb, And two peoples shall be separated from your bowels; And the one people shall be stronger than the other people; And the elder shall serve the younger.
Rifkah is told she has two opposing forces within her, one good one evil. Literally she had two sons in her womb fighting each other. On a deeper more metaphoric level we all have inside ourselves two opposing forces constantly battling each other, one good and one evil.
(כט) וַיָּ֥זֶד יַעֲקֹ֖ב נָזִ֑יד וַיָּבֹ֥א עֵשָׂ֛ו מִן־הַשָּׂדֶ֖ה וְה֥וּא עָיֵֽף׃ (ל) וַיֹּ֨אמֶר עֵשָׂ֜ו אֶֽל־יַעֲקֹ֗ב הַלְעִיטֵ֤נִי נָא֙ מִן־הָאָדֹ֤ם הָאָדֹם֙ הַזֶּ֔ה כִּ֥י עָיֵ֖ף אָנֹ֑כִי עַל־כֵּ֥ן קָרָֽא־שְׁמ֖וֹ אֱדֽוֹם׃ (לא) וַיֹּ֖אמֶר יַעֲקֹ֑ב מִכְרָ֥ה כַיּ֛וֹם אֶת־בְּכֹֽרָתְךָ֖ לִֽי׃ (לב) וַיֹּ֣אמֶר עֵשָׂ֔ו הִנֵּ֛ה אָנֹכִ֥י הוֹלֵ֖ךְ לָמ֑וּת וְלָמָּה־זֶּ֥ה לִ֖י בְּכֹרָֽה׃ (לג) וַיֹּ֣אמֶר יַעֲקֹ֗ב הִשָּׁ֤בְעָה לִּי֙ כַּיּ֔וֹם וַיִּשָּׁבַ֖ע ל֑וֹ וַיִּמְכֹּ֥ר אֶת־בְּכֹרָת֖וֹ לְיַעֲקֹֽב׃
(לד) וְיַעֲקֹ֞ב נָתַ֣ן לְעֵשָׂ֗ו לֶ֚חֶם וּנְזִ֣יד עֲדָשִׁ֔ים וַיֹּ֣אכַל וַיֵּ֔שְׁתְּ וַיָּ֖קָם וַיֵּלַ֑ךְ וַיִּ֥בֶז עֵשָׂ֖ו אֶת־הַבְּכֹרָֽה׃
(29) And Jacob sod pottage; and Esau came in from the field, and he was faint. (30) And Esau said to Jacob: ‘Let me swallow, I pray thee, some of this red, red pottage; for I am faint.’ Therefore was his name called Edom. (31) And Jacob said: ‘Sell me first thy birth right.’ (32) And Esau said: ‘Behold, I am at the point to die; and what profit shall the birthright do to me?’ (33) And Jacob said: ‘Swear to me first’; and he swore unto him; and he sold his birthright unto Jacob.
(34) And Jacob gave Esau bread and pottage of lentils; and he did eat and drink, and rose up, and went his way. So Esau despised his birthright.