I've only owned 3 smartphones since they've been a thing. My first one was Sony's first attempt at a 'gaming" phone and that thing was absolute junk, got rid of it fairly quick. I then tried Samsung's Note, think it was the 2 or 3 and used that for YEARS. I only ended up upgrading because I accidentally threw it down the stairs (it was in my jacket pocket, forgot about it) when I was getting my laundry ready. That throw fucked up the screen but it still worked but ultimately the screen eventually became unusable and although I probably could replaced it, figured might as well finally get a new one after the tenure that one had.

I'm on a Note 8 now, got it in 2016 after that mishap and have been using that ever since. Battery seems decent but I'm not a game user or use any apps that are resource heavy so that likely helps a lot. So my vote goes to the Notes although I'm willing to bet many smartphones can go longer than you think as long as you take care of them and don't abuse the hell out of them like I see many do.