Samsung Galaxy S10e
Hear me out for a second. You can't get a small phone that's any good, you just can't. That said, Samsung's latest Galaxy S10e is the smallest "flagship" phone the company has released in years, making it a great option for most people.
We used to have the Galaxy A7 or A8 here, but they're too big now.
With the Galaxy S10e you're getting a 5.8-inch screen that's completely flat, but the bezels are so small that they had to cut a circle out of the screen for the front-facing camera. The entire front is all screen, which is why they're able to fit a massive 5.8-inch screen on a phone the same size as most 4.7-inch devices from a few years ago. It's smaller than a Galaxy S9, iPhone Xs, and other phones with a screen this big. It's very compact, all things considered.
You're getting the same premium high-end Galaxy S10 experience only with a few things missing and a lower price point. That includes a 1080p HD AMOLED display, Snapdragon 855 processor with 6GB of RAM, 128GB of storage, dual rear-cameras, wireless charging, a 3.5mm headphone jack and a bunch more for $749.
It's the smallest high-end Samsung phone around, which is basically all you really need to know. Get it from any carrier in the US, or from Samsung for $749.