I have decompiled APK using apktool d demoapp.apk then compiling apk using apktool b demoapp.apk but at compile time it throws the error
brut.androlib.AndrolibException: brut.common.BrutException: could not exec (exit code = 1):
Here No resource identifier found for attribute preserveLegacyExternalStorage in package android
The same error appears for requestLegacyExternalStorage as well
If you just want to modify its source before recompile it (resource will not be modified), use -r flag when decompile the apk. I have the same problem, and always get unknown resource problem when recompile it. It solve when I use -r flag when decompile the apk.
# apktool -r d demo.apk
You should compile against SDK 29 and maybe use the most recent build tools for aapt to know this attribute.