Personal GM tips
No matter how much of a secret you want to keep your game, the plot twists and such that you want to have, you should establish with your party what type of game they want to play.
No there might not be a perfect mix but you can come together to make a make game

And with this in mind you can also lead by telling your players what sort of game you would like to run. If the players know you want to have a semi-serious dungeon crawl then they'll know if that's the game for them or not, they'll also have an understanding of what you want!

Not giving distinct details on what sort of game you want to run And then diving into it creates issues. Players may have expectations or hopes that are never approached and they're not comfortable enough to bring it up. I've been that player, and I was kind of miserable.

I ended up being blindsided by something I didn't expect to happen and we were already six sessions in and I was really uncomfortable but I felt like if I just left I'd be letting the people who enjoyed it down, I know that I I could have and should have left now but it sucks.

If you establish with your party that both you and they want a epic battle focused around a heavy amount of lore they know what to expect. If it turns out someone expected it to be more light-hearted and then their NPC partner dies, It's a lot. There's more to that but later.

The GM and party tell the story together. They should be on the same page of what story everyone wants to tell. You can disagree as this is an opinion but every one at the table should be having fun, fun should not be at the expense of someone else.

And if there is a party member who intentionally wants to derail it, is not involved in the way you would like there should be a conversation that isn't focused on shaming, it's focused on "is this the game you want to play?"

Your favorite people might not be your favorite party

Also notice that I've started saying party instead of players because I prefer the comparison that the person running the game is also considered a player, another personal preference haha