Hello raspelin,
Then may you run battery report? see if the battery is having expected capacity and charging as expected?
Please refer to our battery test configuration at the bottom of our official website.
https://www.asus.com/Laptops/For-Home/ZenBook/ZenBook-14-UX434/ Battery life test configuration: Intel® Core™ i7-10510U, 8GB RAM, FHD display, 512GB PCIe® SSD. Battery tests conducted by ASUS in July 2019 using the MobileMark® 2014 Office Productivity scenario. Test settings: Wi-Fi enabled, display brightness set to 150nits, ScreenPad turned off. Actual battery life may vary depending on product configuration, usage, operational conditions and power management settings. Battery life will decrease over the lifetime of the battery. With ScreenPad turned on, the battery life was 10.1 hours.
Thank you.