What is the maximum resolution of an external monitor in Windows on a MacBook Air?

Question

Monitors

Greetings! I want to buy an external display for my MacBook Air 2015.
I'm looking for newfangled 2K and wide monitors.
And on a laptop through bootstrap I use only Windows 10.
I come to stores with my laptop and cable. I connect to monitors.
The maximum resolution that allows you to set a laptop is 1920 * 1080.
But I also need 2k and wide.
and the specification for the notebook states:
Dual-screen and video duplication modes: simultaneous support for full native resolution on the built-in screen and up to 3840x2160 pixels on an external monitor; high color rendering quality in both cases (millions of colors).
Am I doing something wrong?
Do I have a chance on Windows for something more than 1920*1080?

Answer 1

Of course I do "Expand") I
use a thunderbolt - hdmi cable.