[Athanase]

Hello,

The finesse and straightness of the gripping part reminds me more of the Filipino handles (talibong or pira etc...).
If it's Indonesian, I was seeing something from Sumatra and more from the first half of the 20th century. The pattern reminds me of what you can see on certain batak and minang floral engravings but never on handles.
A very stylized Nias balato grip is also a solution but the Timor group D grips are really very close and would perhaps be the best solution.

It's really not easy!