simple:
If you already have google play blue archive. Back up the obb.
Then uninstall blue archivu.
Download Blue Archive (Global) Ver. 1.63.281025 MOD Menu APK | No Skill CD, Damage & Defense
unzip file.
Install "original.apk"
Install launcher.apk
Restore obb (if you dont then you will have to download ~5gb of game data,result is the same but if you saved obb and restore obb it saves alot of time!)
Open launcher.apk
Enjoy.