Could be bias from it beeing my primary device for roughly 1.5 years now, but the Steam Deck is very high up there for me. While it lacks a bit in some button quality and I'm particularly not a fan of how it feels to reach the bumpers, it makes up for it with options. You have all of the buttons on a standard controller, all of the features of a Steam Controller, an extra two back buttons, and a touch screen for when that fairly niche option applies. Pretty much any game can be made to control reasonably well. Jack-of-all-trades master of none is probably the best way to describe it. I will also note that the OLED model give this a nice bump. As the dpad and bumpers on the LCD were not very good.
If we want to limit this to traditional controllers, though, my vote would be the dualshock 4. That's the layout I grew up with and it improves on older models with actual triggers and extended grips for my now adult-sized hands. As a primarily PC player, the touch bar can also come in handy in a pinch by being able to map 2 additional buttons to it.