So, after 149 chapters, four years and a lot of shit happened, Wano ended. A bit of hate&love arc, for sure, but - alas - seeing all of this ending put a smile on my face. An hype smile, seeing as we don't have any idea, cliffhanger or hint to what will come next. While I don't doubt it will be a long-waited arc (Elbaf, Ace's grave or whatever), it is since Fishmen Island we didn't have the void waiting for us. Such an awesome feeling.
BTW the smile easily fades away. I loved Yamato in all of his points and I feel like this ending-not-ending is kinda of a mess, to say it less. While I highly encouraged for him to join the crew, I'd have preferred a clear "no" to this "well see ya later" which kinda sounds like Jinbe before. I mean, I will happily accept Yama, Kin and Momo all together on the ship, but I don't think we have a lot of time ahead of us to enjoy crewmates that will join even later than now. Surely Yamato doesn't look like a character which met his narrative closure.
The Hiyori/Orochi thing is a bit ambiguous but I'll try to put what the poor Japanese I know allowed me to understand of the original scene. Hiyori's claim basically trace Oden's sign line, which in JAP sounds like "Niente nanbo no!!! 'Oden' ni soro!!!", where Oden works like both his name and the dish name. The official translation "I am Oden, I am born to boil" is kinda a compromise with the unique original Japanese meaning, which uses the structure "[X] nanbo no!!! [Y] ni soro!!!"`, which works like: "[Y] is what it is cause [X]". Oden's full pun can be translated like "the Oden is what it is cause it boils", transferred on himself like "I am Oden cause I boil (like Oden, but metaphorically)".
Hiyori instead claims "Moeru nanbo no!!! 'Kurozumi' ni soro!!!", where Kurozumi works for both Orochi's clan name and 'black charcoal'. The literal translation should sound like "the charcoal is what it is cause it burns", which on Orochi become "You are what you are (a charcoal) cause you burn (like charcoal)". So the point is she's not saying that Orochi is born to be burned down as a Kurozumi clan member, but that he is burning, so he is a charcoal.
If someone knows Japanese better and want to confirm or deny my interpretation, feel free to.