How to have a diplomatic, middle of the road, with Huana, RDC, VTC gameplay/ending?

[NOT The Emperor of Mankind]

So I'm in my second(kinda) play-through now, with the first being a very passionate and kind, and end up siding with Huana.

I mean I didnt finish it yet, but I am way too deep in that territory to do anything about it, therefore the second play-through.

What I want to try and achieve this time:
- Something more diplomatic
- More Middle of the road
- Something that decently satisfies Huana, RDC, and the VTC factions

I don't mind spoilers, so what decisions, actions and paths should I be on the lookout for?
Is/are there something/s I should sure to do/not-do?

Please help

[Du-Vu]

Well, Independent will screw over/piss everyone off equally, so there's that. :\

But honestly, I think the thing that ends up with the best overall results for everybody is siding with Huana, putting Castol in charge of the VTC, and (bear with me) agreeing to hear out Karu's final orders for you (assassinate Queen Onekaza), then refusing -- at which point she orders your death, which aggros the entire Brass Citadel and forces you to fight your way out.

I know that sounds really bad for the RDC, but it's pretty much self defense, and (spoilers) what actually ends up happening is you still shut off the storms over Rauatai, and depending on how you've dealt with Maia, the emperor declares that the RDC was overreaching, making them appear to be a nation of warmongers, and the Kingdom needs to rethink its military policy.

This leads to the Huana only having to deal with one trading company, and the VTC end up being more accomodating. When the Huana take over Ukaizo and reassert their claim to the islands, VTC ends up largely pulling up stakes, other than leaving a token assignment of scientists to continue researching luminous adra. They demote Castol to the position -- but he ends up actually being far happier in that role than he ever was having to worry about margins and quotas.

The Huana flourish, they get to keep their islands and not lose their culture, nobody goes to war, and research and trade still go on. What happens to the Roparu, the Wahaki, Tikawara and so on still depends on how you resolved their quests, but I do think that's the most positive, diplomatic, middle of the road resolution.