Minecraft for Windows 10 is stuck in 4k screen resolution

My computer screen has a 4K resolution, but the full-screen MC runs very slowly with a frame rate of only about 15.
I hope the resolution can be set by myself. Maybe it won't be too slow.
I also hope MineCraft can be optimized better.

OS: Windows 10 Professional 1903
CPU: Intel Core I7-8750H
SSD: Samsung 970 EVO
RAM: 16G
GPU: (Seemingly not used) GTX 1050Ti