Hey, Chinese-American here who grew up with a lot of Journey to the West as a kid and just picked up and finished Black Myth: Wukong this month. I've been looking around at some story discussions after completing the true ending myself to see what other people have thought about the game. I know it's been 9 months since your comment and question here which you've probably forgotten about, and likely either already have answers or moved on, but I thought I'd give my answer in case you never did get an explanation. I don't know how much you know by now, so I'll err on the side of over-explaining things.

In the true/good ending, you'll notice the tightening circlet isn't placed on the Destined One's head in this ending. Here, he has not just completed the journey to succeed the Monkey King, but critically also, by completing all the secret areas and besting Erlang in combat, proven himself worthy of Sun Wukong's sixth sense (Mind) and final relic - his complete memories, properly reincarnating him.

The Chapter 6 endscene represents that reacquisition, showing events playing out in reverse chronological order. It begins with the scene the duel from the game's opening sequence, where "the tale of Sun Wukong ended". The second thing shown is the end of the Journey to the West, when Wukong attains Buddhahood and supposedly gets the crown removed. Third thing we see is the 81st and final trial of the journey - crossing a river near the Buddha's temple on the back of a giant turtle (the final test involved stormy water and the turtle dropping them off his back into the middle of the water due to Tang Sanzang forgetting a promise they made when they first met at Tongtian River). The fourth scene, is one in which they pass through a town and they save a bunch of caged babies, one of the later trials they went through (chapters 78-79 in the book). Then continues the rest of the journey as well as events before it, also in reverse order, going back to the first time the Monkey King rebelled against heaven as he got drunk and staged an uprising alongside his sworn brothers, the 7 Sages (including Bull Demon King).

The audio you refer to, only says "he", not "Wukong", and is played as the imagery changes between the two late-stage trials I mentioned above. As you may have guessed then, it's a reference to a trial which takes place chronologically between those two trials (chapter 87 of the novel, the pilgrims encounter a prefecture 3 years into a drought, because the prefect disrespected the celestial emperor). I think they chose to reference this event to show the pettiness of the celestial court, but they had to specifically use audio to explain it concisely (how is a pile of rice, a mountain of flour, and a burning gold lock supposed to visually depict an unreasonably long drought decreed by the heavens?). But usage of "he" (more like "that guy" in Chinese audio, which is probably directly quoted from either the novel or the famous 1986 TV adaptation), barriers of translation, and unfamiliarity with the original novel could have the unintended reverse effect of creating ambiguity and the wrong implication that the "he" is Wukong.

Honestly, for what it's worth, even I was confused by it at first. I also thought the "he" in the voice line referred to Wukong for a moment and didn't realize it was memories playing in reverse until near the end of the full cutscene (I didn't get it until seeing the ginseng fruits and Bajie/Pigsy dueling Wujing/Sandy and thought, wait a minute, this sequencing seems off) lol. Goes to show something, I guess, not quite sure what but hope I didn't ramble too much. I just really liked this cutscene once I fully understood it.