Hi,
Yes, lovely images of what I believe is still a wilderness. Also, I don't think there is a dam or any other flow control on the river - flow control will alter delta morphology. So, it's probably as pristine as anywhere on Earth.
Delta morphology is controlled by three factors: river flow, wave action and tidal action (see, for example
https://www.e-education.psu.edu/earth107/node/1023,
https://www.researchgate.net/figure/...fig3_275640337) I can't see any indication of tidal influence, which I think is right in that part of the world. The inner section of the delta looks flow dominated but the outer edge is truncated indicating wave control. It's interesting that the delta is only influenced by conditions during summer as it is frozen solid in winter.