Maybe it might be the charging cable. I use a power delivery cable. A regular cable that came with a fast travel charger may charge it slower. Use the pixel or purchase an Anker 18w charger and pair it with the Anker power line cable and hopefully that will help.
Anker Powerline II USB-C to USB-C 3.1 Gen 2 Cable (3ft) with Power Delivery, for Apple MacBook, Huawei Matebook, iPad Pro 2020, Chromebook, Pixel, Switch, and More Type-C Devices/Laptops
https://www.amazon.com/dp/B072JYDQ7N...cUvbUpU7011273