An interesting question!
To avoid confusion, I interpret your question as: (1) why do we have multiple English translations of a single Koine Greek word κύριος; and (2) did the translators of the Septuagint (LXX) only use κὐριος to translate its Hebrew original.
(1) The Greek word κύριος has a wide semantic range. It can simply be used as a polite form of address (this is a feature of both Modern and Koine Greek); it could refer to the person who has authority over a household of men, women, children and servants; and it can have a specific theological meaning when used to refer to God.
Early Christian speakers of Koine Greek would’ve distinguished the usage of κύριος based on context, and modern translators often use different English words in order to capture this nuance (especially where it relates to God) as it wouldn’t be apparent to modern readers.
(2) This is a difficult question as there is no single original. Κύριος is used in the LXX to translate about 13 or 14 different Hebrew
and Aramaic words. Many of these words in Hebrew and Aramaic also refer to God, most famously as a vocal substitute for the tetragrammaton. But it can also have more mundane uses. For example, in Ex 28:21 the LXX translates the Hebrew “the
ba’al of the bull” (in the sense of “owner”) using κύριος.
Insofar as I know, the LXX translators were very consistent and particular in their usage of κύριος when translating various names and titles that referred to God.
Why? Was the greek language that insufficient? Did the latin render multiple translations of kyrios?
This is a feature of all translations of Hebrew when referring to God. Hebrew words such as
'el,
'elah,
'elohim,
'eloah,
ba’al (amongst several others) that refer to God have no direct and separate correspondents in any other language.
The Latin Vulgate, if I’m remembering correctly, is quite consistent about translating the LXX and New Testament κὐριος into
dominus. As for the Old Testament, I’m unsure where he differed with the LXX in respect to translating the various different Hebrew and Aramaic terms used to refer to God. The scholarship is muddy because we’re unsure of what texts (Greek or Hebrew) Jerome used as the basis for his Old Testament translation. This is in contrast to modern translations that use the Masoretic Text which date several centuries after Jerome.