Genesis 25:1-6 (NKJV)
Abraham and Keturah

25 Abraham again took a wife, and her name was Keturah.

The Hebrew word “Keturah” means prayer incense which was burnt on the altar incense in the Tabernacle of Moses, And that same incense also became a sweet smelling aroma in the nostrils of God.

Hagar the Egyptian woman returns, and her name is changed to Keturah:

The return of Hagar was also a symbolic sign of the transformation of Hagar (Bond woman), transforming into Keturah (prayer incense)

Genesis 25:2-6

2 And she bore him Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. 3 Jokshan begot Sheba and Dedan. And the sons of Dedan were Asshurim, Letushim, and Leummim.

4 And the sons of Midian were Ephah, Epher, Hanoch, Abidah, and Eldaah. All these were the children of Keturah.

5 And Abraham gave all that he had to Isaac.

6 But Abraham gave gifts to the sons of the concubines which Abraham had; and while he was still living he sent them eastward, away from Isaac his son, to the country of the east.

Where did the children of Ketura go after separating from Isaac?

They went eastward;

According to the Jewish commentary, from the location where Abraham was, eastward becomes the present day India.

Being the location where the children of Keturah went and became Hindu priests…