From my personal experience after using Xiaomi phones and their MIUI for 5 years now, MIUI is digusting in terms of bugs and battery perfomance, i am using now Mi 11 Lite 5G and everything is amazing about the device, but android system is taking up to 40% battery usage sometimes, and that is MIUI's fault, its not hardware fault for sure... cant wait for new update....Okay then, looks like you are right then. How is that possible that Xioami kills performance of their phones with OS is just beyond me. But still they are not bad in terms of efficiency, many Xiaomi phones leading battery charts. So I assume other companies are even worse. Wish to try custom ROM but for safety reasons I don't want to.