Maybe I should clarify. I am not looking for a hex crawl. Just a game where the plot can resolve in a non linear fashion.
If by "the plot can resolve in a non linear fashion", you mean "there is more than one endgame state for the adventure, including or solely consisting of endgame states the players choose for themselves", then 5e adventures as written aren't really suitable.
Tomb of Annihilation, Princes of the Apocalypse, Curse of Strahd, and Storm King's Thunder are all pretty sandbox-y, but they each have a single endgame state that the PCs are working towards, one that is set by the context of the adventure itself.
If you mean "there's no single set path to get to the endgame state", then those adventures are all pretty suitable. For Tomb of Annihilation, I would suggest slowing down the doom clock, and to my mind Princes of the Apocalypse would need more "side content" to really fit the bill.
Tomb of Annihilation is a hexcrawl, so if you specifically don't want to play one, it's not going to work for you. On the other hand, it probably has the most potential to be a sandbox where the players decide what the endgame state is, if you're willing to ignore the adventure's central goal and are ready to add content tailored to the PCs' ambitions.
