I am unable to generate Signed APK using minifyEnabled true and shrinkResources true
App Level : build.gradle
buildscript {
This :app:proguardRelease UP-TO-DATE .. makes this log not complete enough to say if this answer will help or not.
Please do clean + build release again to have full log with all steps, you may want also to add --info to gradle options, or even --debug to get more diagnostic messages in gradle build log.
Clean+build may also fix some weird problem of gradle/other-tool not correctly updating some file and reusing older incorrect one - rarely happens.
Also try to switch minification OFF (not solution, just experiment), whether it helps (to localize the problem is really with proguard minification and not elsewhere).
And of course if there are proguard related errors during minification, try to follow advice from the linked answer.