Not spoilers, because I know nothing. Simply speculation. Simply putting it out there.
So, the big question for the state of Thedas at the end of Veilguard is likely to be whether or not the Veil remains, correct? Given that, and given how many people still talk about how ME3 ended and the problem that popped up that resulted in Andromeda going to another galaxy...
I don't think they'll do that again. I don't think people will get to choose whether or not the Veil remains. I think it'll be a set, scripted event, that'll happen the same for everyone. Why? Practical reasons. One of the big reasons they chose to move Mass Effect Andromeda to another galaxy was because the choice at the end of ME3 meant that, theoretically, there should be 3 wildly different world states for a sequel to be happening in. And not a simple, this character survived or didn't, here's a stand in character instead, but on a massive scale. It would have been stupidly expensive to basically create 3 different games, depending on the starting point.
It's the same with Veilguard. Theoretically, with the way it's been put to us up until now, whether or not the Veil still exists will have big consequences, and could potentially change a lot of things about the state of the world. So, I think it'll happen the same in game (possibly with small variations based on player actions) for everyone. Because otherwise, their choices for a sequel are 1. Spend the resources to make 2 fundamentally different worlds (EA would never) 2. Make it so that, oh, nevermind, it really wasn't a big deal, and things are mostly the same (Doubt it, it's a cop out, and one fans wouldn't like) or 3. Pick one as Canon and only make a sequel based on that state (Again, doubt it, because fans would be pissed).
So, my guess for the game is that we're not actually going to be able to choose whether or not the Veil remains. Because that choice would put Bioware in a bad spot for the sequel, and I think they know that.
Hopefully, people won't be too mad, if that does end up being the case. Because from a storytelling/ game making perspective, I think it would be the best choice, even if I think there is likely to be a chunk of fans that don't like it.