I know we had a conversation about this in the past, but I don't believe the kjv Translators had a horse like mystical animal in mind when the chose "unicorn". For their translation. A unicorn does not have to be the mystical version. It simply means an animal having one horn. The kjv is always accurate as the English was spoken in 1600.
(ASV) God bringeth him forth out of Egypt; He hath as it were the strength of the wild-ox: He shall eat up the nations his adversaries, And shall break their bones in pieces, And smite them through with his arrows.
(ESV) God brings him out of Egypt and is for him like the horns of the wild ox; he shall eat up the nations, his adversaries, and shall break their bones in pieces and pierce them through with his arrows.
(LITV) God who has brought him out of Egypt is for him like the lofty horns of the wild ox; he shall eat up the nations that are his foes, and shall break their bones in pieces, and shall pierce them through with his arrows.
(MKJV) God brought him forth out of Egypt. He has as it were the strength of an ox. He shall eat up the nations, his enemies, and shall break their bones, and pierce them through with his arrows.
Even the MKJV wouldn't translate it as "unicorn" but rather as "ox," but more accurately as "wild ox," which were larger and stronger. A generic word like "one-horn" is not a good translation.
The Douay Rheims or Catholic translation rendered the word as "rhinoceros."
(DRB) God hath brought him out of Egypt, whose strength is like to the
rhinoceros. They shall devour the nations that are his enemies, and break their bones, and pierce them with arrows.
--Considering the geography of the land I don't think that is an accurate translation. But I do think it is better than "unicorn."