If there is one only God why are there three different words which mean God?

Question

The most common word translated as "God" is אֱלֹהִים, elohim which is plural. In addition to elohim, two singular words, אֵל el and אֱלוֹהַּ eloha translated "God." Occasionally two different words are used in the same verse, both of which mean "God." Here are three examples of this:

1. El tells Jacob He is Elohim of his father:

And He said, “I am God, the God of your father. Fear not to go down to Egypt, for I will make you there into a great nation. (Genesis 46:3 NJPS)
וַיֹּאמֶר אָנֹכִי הָאֵל אֱלֹהֵי אָבִיךָ אַל־תִּירָא מֵרְדָה מִצְרַיְמָה כִּֽי־לְגוֹי גָּדוֹל אֲשִֽׂימְךָ שָֽׁם

2. David composed a song with a line asking who is Eloha except YHVH and who is a rock but Elohim:

Truly, who is a god except the LORD, who is a rock but our God? (Psalm 18:31 [32])
כִּי מִי אֱלוֹהַּ מִבַּלְעֲדֵי יְהוָה וּמִי צוּר זוּלָתִי אֱלֹהֵֽינוּ

3. Job complains those who provoke El are secure and Eloha provides for them:

Robbers live untroubled in their tents, and those who provoke God are secure, those who God's hands have produced. (Job 12:6)
יִשְׁלָיוּ אֹֽהָלִים לְשֹׁדְדִים וּֽבַטֻּחוֹת לְמַרְגִּיזֵי אֵל לַאֲשֶׁר הֵבִיא אֱלוֹהַּ בְּיָדֽוֹ

Each of these examples seems to say there is more than one God, or, that the meaning of "one" God is more complex than a numerical "1."

If there is only one God, why are there three different words which mean God?

Answer 1

The answer to this question becomes theological as much as linguistic. The very short version:

As the historical-critical method developed in the era of modern Biblical interpretation, scholars identified the fact that there were different words for God (including Jehovah and Elohim). These scholars become convinced that these different names reflected different/competing textual traditions (often referred to as "J" and "E") that were eventually merged together (textually) at a later period of time. ¹ Most of these scholars subscribe to the idea that different Biblical texts should be read and interpreted individually and that they cannot necessarily be reconciled with the point of view of another. ²

For those inclined to view the Bible as being internally (and doctrinally) consistent, the use of different names for God in the Old Testament would be attributed with God's attempt to reveal different aspects of His divine character through the different names and titles by which He has revealed Himself to mankind. ³

^{(1) Michael D. Coogan, "Introduction," in The Oxford Handbook of Biblical Studies, ed. J.W. Rogerson and Judith M. Lieu (Oxford: Oxford University Press, 2006), 6.}

^{(2) Ehrman, Bart D. An Introduction to the New Testament. 7th ed. (Grand Rapids, MI: William B. Eerdmans Publishing Company, 2019), 15.}

^{(3) Blue Letter Bible's The Names of God in the Old Testament}