Others are sometimes the required files by the apps you use, So cannot be removed. Similarly System will never be removed because of the actual system OS and files.
Hello, System Memory can not be clear as it contains some of file that requires to operate your phone, similarly other's Memory can not be fully cleared bt u can clear some part of it by removing files from apps manually
Other memory is lije whatsapp chats, whatsapp images, whatsapp videos same as of telegram clear them to increase space And also try to clear chache memory of app
