First watch this and try reinstall - https://youtu.be/trHinrIm6DM
After if you get "Could not initialize class org.codehaus.groovy.runtime.InvokerHelper"
1.install Java SDK 14 and update env path.
2."[Your RN or Flutter Project Folder]\android\gradle\wrapper\gradle-wrapper.properties" this file edit as ...(upgrade gradle version)
#Fri Jun 23 08:50:38 CEST 2017
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-all.zip
3.run gradlew in cmd path "[Your RN or Flutter Project Folder]\android\"
4.it takes time.after if shows "BUILD SUCCESSFUL" you can "flutter run" in ur project folder
Yeah It's work 👍