Quoting Commentary for I Kings 10:13

In addition, Malkat Sheva’s visit stands out as the only visit by a foreign dignitary who expresses such positive feelings about Hashem (perhaps except for Phoenician king Chiram). Where are the other kings who visit and are motivated to praise Hashem? It seems that this never happened. Thus, Shlomo HaMelech’s dream to positively impact the leaders and peoples of the world to recognize Hashem hardly materializes. Moreover, Melachim I 10:13 records Malkat Sheva’s return to her land, but does not mention an attempt made on her part to inspire her subjects in the belief in Hashem as the one and only God.

aside from that which she brought This is written here in deference to the honor of the kings of Judah; it means that she gave him more than he gave her, and in I Kings (10:13) it is written: “aside from that which he gave her according to King [Solomon’s] ability.” [He gave her] things that were common in the land of Israel, but were not common in her country.

What is [the meaning of] the queen of Sheba? The kingdom of Sheba: At first glance, this is difficult. Since all of the content that is stated about the queen of Sheba is in the feminine form, until it ends, and she and her attendants left and returned to her land (I Kings 10:13), implying like the straightforward understanding of the verse, that she was a female! And why is it not stated like this about the other kingdoms, [the queen of x] is to mean the kingdom? So it should be explained that this is what it is saying: Anyone who says that the queen of Sheba is a woman who did not reign but rather was the wife of a king, and that is why she was called the queen of Sheba — the explanation of queen being the wife of a king, coming in the way of all the kingdoms — is nothing but mistaken. So what is [the meaning of] the queen of Sheba? That she is the queen of Sheba on her own and she herself reigns. And even today, there are kingdoms in which a woman reigns there, and it is easy to understand.