Stephen D. Ricks et al. discuss etymology of "Angola."
“Angola,” in Dictionary of Proper Names and Foreign Words in the Book of Mormon, ed. Stephen D. Ricks, Paul Y. Hoskisson, Robert F. Smith, and John Gee (Orem, UT: Interpreter Foundation; Salt Lake City: Eborn Books, 2022), 46
ANGOLA is the name of a Nephite city. if the name is from a Hebrew root, it may be a combination of words, since the Hebrew letter nun in contact with any other consonant within a word would make it subject to “regressive/anticipatory assimilation” (i.e., ng or gn becomes gg). Thus, the name may derive from the Hebrew ‘ayn, “spring, well,” and a word from the Hebrew/Semitic root √glh, “to uncover, reveal; to emigrate, to into exile,” or gll, with the basic meaning of “to roll, roll away (a rock or stone).” A combination of ‘ayn plus a form of either of the roots may generate the names “rock spring,” “emigration, exile spring.” An Egyptian etymology is also possible, as if one from an indigenous language.