Which "physical buttons"? Almost all have physical volume/power keys, but I doubt that any with that spec will have physical home/back/multitasking buttons.
The closest that comes to mind are the Samsung Galaxy S7 series: these have 16:9 displays, physical home buttons, s820 SoC (or the equivalent Exynos, depending on where you are) + 4GB RAM. But it's 3 years old. However more recent phones won't have physical buttons on the front (or not the higher-end ones, which you've also said you were after), and almost nothing high-end that's less than 2 years old will have a 16:9 screen.