This is all sooooo very weird.
Ok, so. I *don't* find it far fetched that Tyrion would ultimately betray J/D, although I do find the whole "I wanted to keep my family in power" reasoning very odd. I could see Tyrion wanting to protect his family out of some kind of benevolent instinct he cannot fight against, even when it comes to Cersei, but there have been literally no signs whatsoever that he was genuinely invested in keeping the Lannisters in power. To me, suddenly having him do a 180 and suggest that all along he didn't care about the realm, loved his family and wanted the Lannisters to be the absolute rulers is something I struggle to wrap my mind around. That's like... 7 seasons of characterization more or less thrown out of a window. Also, he was the one who did NOT want D.any attacking KL with her dragons and now he's all "they can all die because they didn't support me in my trial years ago"? Uh?
Brienne STILL being the Starklings bodyguard is pseudoridiculous at this point. I honestly do not think George is aiming to end the story with Brienne being a glorified bodyguard for life.
Davos wearing the Hand of the King pin is interesting. Because most will obviously assume that means Jon is King but... isn't it interesting that it was Nikolaj who talked about how much he liked working with Davos? I always assumed that if Jaime became King, Tyrion would be his Hand, but if it is true that Tyrion conspired with Cersei, then I can see why Davos is the best choice.
This still does not address AT ALL why Emilia would be so "fucked up" by the "lasting flavor of what Daenerys is". If Tyrion did indeed betray them all, she would still be the victim, so even if, say, she burns him alive, well... he kind of deserved it?
The only potential interesting aspect about Tyrion betraying them all is to flip the "good Lannister/bad Lannister trope" on its head. It would be interesting to see Jaime become the good, honorable Lannister, while Tyrion becomes the evil, scheming one. It might also explain the "heartbreaking" part of Jaime's story, if he has to face the fact that he's literally alone in the world, his family all having thrown honor away for power. But it still doesn't fully address how much Tyrion owes and loves Jaime, if they claim the betrayal is about power and not love.
This is so NOT the climax of the series. There is no way that this is the main event, with all but one of the main protagonists missing and/or DISCO, and a collection of supporting characters as a jury, including people we have never even seen before. Something is very very fishy here.