For example, in Divrei Hayamim Beth 36:4, the king of Egypt crowned Eliakim over Judah and Jerusalem, and he changed his name to Jehoiakim. In Melachim Beth 24:17 the king of Babylonia crowned Mattaniah, and changed his name to Zedekiah. In the Book of Daniel, the chief officer of Nebuchadnezzar changed the name of Daniel to Belteshazzar, Hananiah to Shadrach, Mishael to Meshach, and Azariah to Abed-nego. Why did they change their names? Did they try to change their Jewish identity? Was there anything in these names that was incompatible with their religions? Or they just wanted to impose their power?
Da'at Mikrah write in their introduction to the Book of Jeremiah:
"...Instead of him [=King Yehoachaz], appointed Nekho Eliakim ben Yoshiyahu, who agreed, it seems, to be subject to Egypt, and even changed his name of Eliakim to the name Yehoyakim (most likely, as if to tell him, that he rules by the benevolence of the king of Egypt). [...] Instead of Yehoyachin, placed Nevuchadretzar Matnaya, third son of Yoshiyahu, upon the throne, and changed his name to Tzidkiyahu, the same way that Pharaoh Nekho changed the name of Eliakim to Yehoyakim, probably from the same reason, to show the world that Tzidkiyahu isn't but a servant of Babylon."
It seems, therefore, that the name-change stemmed from want of imposing power, in particular considering that those were very restless times in the Middle East, filled with wars and rebellions.
So with regards to Doniel having his named changed to Beltshatzar -
TZAFNAT PANEAH. As the Targum [Onkelos] has it, and this is from the Egyptian language. And it was their practice to call a person, when they appointed him over their household, by an appropriate name. Thus (Num. 13:16), "Moshe called Hoshea bin Nun Yehoshua" when he became his servant. Thus he [the king] called Daniel Beltshatzar, as it is written (Dan. 4:5), "whose name is Beltshatzar, after the name of my god." (Sefaria translation and notation)
So it would seem that it was a common thing to do across multiple cultures - namely Jewish and non-Jewish, when the given person is given a position of authority.
The Rashbam repeats this comment later in Bamidbar 13:16:
ויקרא משה להושע בן נון יהושע, this does not mean that the people from then on called this man Joshua. It means that the man who had been referred to as Hosheah son of Nun in his father’s house was the one whom Moses now referred to as Joshua. The change had occurred already at the time when Moses appointed this man to be his personal valet. It was customary to change the names of people who were promoted in rank. We find this the first time when Pharaoh changed Joseph’s name to Tzafnat Paneach (Genesis 41,45) We find it again in Daniel 1,6 when Nevuchadnezzar’s chief officer changed Daniel’s name to Belteshazzar. This had been a reference to a Babylonian idol so named. The first time Joshua’s name had been changed was in Exodus 24,13.
The fact that their names were changed into a different language is possibly due to it being the spoken language of the one who promoted them.
This idea is also brought by the Tur Ha'Aruch there in Bereishis.