Copying files from AWS Appruner to S3

I am planning to use AWS Apprunner to run my load test using JMeter.

The Apprunner service is configured to use my github repo which contains only 2 files(Jmx file and shell script which to downloads jmeter and run the load test)— till this part is working fine. However I am looking for option to copy the test result file into S3 bucket.

One option which I could think of is create rest call with API gateway for S3 put and use the curl command within the apprunner container after the test completion.

Also I have set one environment variable while creating Apprunner service - How can I access it in above shell. example: MYTESTNAME = CUSTOMER-VAL

I tried echo $MYTESTNAME - it prints as $MYTESTNAME

Appreciate if someone can help.