When your App Get Blocked during the launch and it shows "APK Signature tampering detected"
Please follow the below instruction to remediate this.
Google Play Console App signing key Guide
When you create a release there will be an option to change the app key signing Click -> Change Signing key and in the pop up dialog Click Change app signing key
There will be four options displayed select the third option -> Export and upload a key from Java Keystore
Download the PEPK tool and you must have the path of the keyStore file, and you need output file path to generate the ZIP file using the command below
$ java -jar pepk.jar --keystore=C:\Users\Desktop\demo.jks --alias=demo --output= C:\Users\Desktop\output.zip --include-cert --encryptionkey=eb10fe8f7c7c9df715022017b00c6471f8ba8170b13049a11e6c09ffe3056a104a3bbe4ac5a955f4ba4fe93fc8cef27558a3eb9d2a529a2092761fb833b656cd48b9de6a
Running this command in Command Prompt will generate a zip file which you have to upload it by clicking on the Upload protected ZIP
After upload the ZIP file you will see the Save button enabled click it and save it.
Once done now you can navigate to Setup -> App Integrity -> App Signing
you can see the updated app key signing certificate.
Now both App signing key certificate and upload key certificate will have the same values.