There’s nothing we can do about this. Virus scanners don’t reveal their methodology for how they detect apps because that means that people who write real viruses could just work around it. Therefore, we don’t know why Huawei and Xiaomi devices continue to flag App Inventor apps as malware. Presumably, if Google thought App Inventor was malware they would remove the companion from the Play Store, along with every app ever made with App Inventor.