I saw something similar today with Open Document Reader. In its case, it’s a manifest failure:
failed to install at.tomtasche.reader_164.apk: Failure [INSTALL_PARSE_FAILED_MANIFEST_MALFORMED: Failed parse during installPackageLI: /data/app/vmdl662567906.tmp/base.apk (at Binary XML file line #64): at.tomtasche.reader.ui.activity.MainActivity: Targeting S+ (version 31 and above) requires that an explicit value for android:exported be defined when intent filters are present]