A sideloaded app can usually be updated in place only when the replacement keeps the same package identity, compatible signing key and acceptable version code. Back up before testing risky changes.
‘App not installed’ is a symptom, not one error. Check storage, package completeness, signatures, version codes, Android requirements and conflicts before deleting data.
A safer APK installation process keeps Play Protect and other protections enabled, grants install permission only to the source you use, and checks package compatibility first.
APK, XAPK, APKS and AAB are not interchangeable. Learn which formats Android installs directly, which are containers, and why missing split packages cause failures.