Do not hoping too much if there is a pocket camera that claims to have 4K feature, because it could be 4K capabilities are not optimal, most camera only able to record video for 5 minutes then overheat. For example, The Sony RX100 V camera that has a price of thousands USD just the same thing, and it records a video for 5 minutes or more batteries can be exhausted if used to record video with 4K quality. The Panasonic LX10 camera is limited to just 15 minutes to record 4K video and some 4K cameras not more than 20fps.
Note also whether the camera captures all areas of the sensor is used or cropped (only partly), because it will affect the catch and field of the view become less wide if cropped as happened in the camera Panasonic LX10.
The point is not to get dazzled first, explore the 4K camera's capabilities first and do not be rash to buy if not too need 4K, buy a cheaper even though his fps maximum 1080p is also enough or buy a second hand 4K camera, because not too much people see youtube videos with 4K quality, most of them see youtube with smartphones.
The 4K feature in the pocket camera I think is still a gimmick, just to attract people to buy even more expensive. Or be careful with 4K features in cheap actioncam, may 4K feature is only 15fps or bitrate quality and the lens is very bad, so 4K feature becomes useless.
Let us not be fooled, read and see the product review first before buying. Hope be useful.