The curses in Ki Tavo end:

And the LORD shall bring thee back into Egypt in ships, by the way whereof I said unto thee: ‘Thou shalt see it no more again’; and there ye shall sell yourselves unto your enemies for bondmen and for bondwoman, and no man shall buy you. (Deuteronomy 28:68)

וֶהֱשִׁיבְךָ ה' מִצְרַיִם בׇּאֳנִיּוֹת, בַּדֶּרֶךְ אֲשֶׁר אָמַרְתִּי לְךָ לֹא תֹסִיף עוֹד לִרְאֹתָהּ. וְהִתְמַכַּרְתֶּם שָׁם לְאֹיְבֶיךָ לַעֲבָדִים וְלִשְׁפָחוֹת – וְאֵין קֹנֶה. (דברים כ"ח, סח)

Several difficulties arise. If Israel returns in ships, how is that the way He said “Thou shalt see it no more again”? It is not their route out of Egypt. What does specifying ships add? And the image is unusual, since no maritime connection between Canaan and Egypt is known from biblical times.

Jacob Zvi ben Gamliel Mecklenburg (1785–1865), in HaKetav VeHaKabbalah, explains oniyyot as sorrow and sadness rather than plural ships, like Lamentations’ “And He hath multiplied in the daughter of Judah Mourning and moaning” (2:5). The verse would mean the LORD returns Israel to Egypt in sorrow.

An interesting parallel occurs in Isaiah:

… And I will bring down all of them as fugitives, even the Chaldeans, in the ships of their shouting. (Isaiah 43:14)

... וְהוֹרַדְתִּי בָרִיחִים כֻּלָּם, וְכַשְׂדִּים בָּאֳנִיּוֹת רִנָּתָם. (מ"ג, יד)

On this interpretation, the LORD brings down the city’s bars and the Chaldeans as they raise their voices in sorrow. Rinnah means raising the voice, not necessarily singing, as in “And there went a cry throughout the host” (I Kings 22:36), and “Arise, cry out in the night” (Lamentations 2:19), whose context means crying loudly. The JPS quotation above instead reads ships and fugitives; the author proposes an alternative reading of the same Hebrew words.

If this seems implausible, you may be surprised that the New English Bible translates precisely this way:

The LORD will bring you sorrowing back to Egypt by that very road of which I said to you, ’You shall not see that road again; and there you will offer to sell yourselves to your enemies as slaves and slave-girls, but there will be no buyer. (Deuteronomy 28:68, New English Bible)

Incidentally, HaKetav VeHaKabbalah interprets ani in Exodus 11:4 similarly to avoid anthropomorphism:

“And Moses said: Thus saith the LORD: About midnight will I go out into the midst of Egypt”: I think “ani” should be explained from “mourning and moaning” (Lamentations 2:5), and “go out” like “The thing proceedeth from the LORD” (Genesis 24:50). Its meaning is: around midnight, great mourning and lamentation will arise within Egypt.

"וַיֹּאמֶר מֹשֶׁה: כֹּה אָמַר ה', כַּחֲצֹת הַלַּיְלָה אֲנִי יוֹצֵא בְּתוֹךְ מִצְרָיִם": ולי נראה לפרש מילת "אני", מן "תאניה ואניה" (איכה ב', ה), ומילת "יוצא" כענין "מה' יצא הדבר" (בראשית כ"ד, נ), וטעמו: כחצות הלילה יתיילד בתוך מצרים אבל והספד גדול.

Unlike his interpretation in Ki Tavo, however, his Exodus interpretation is difficult to regard as the plain meaning.