How to export parameters from aws parameter store and import into another account

I created a utility which does exactly what you want:

pip install aws-ssm-copy
aws-ssm-copy --dry-run --source-profile <source> --recursive /

Checkout the aws-ssm-copy utility and blog for more details.

1. Retrieve all parameters via aws ssm get-parameters-by-path --path "/relative/path/" --recursive
2. Write the resulting JSON somewhere down - e.g. into a file
3. Prepare put commands e.g. with JS

for (const value of params.Parameters) {
    const { Name, Value } = value;
    console.log(`aws ssm put-parameter --name "${Name}" --value "${Value}" --type "String"`);
}

May be get-parameters-by-path suits here: aws ssm get-parameters-by-path --path "/" --recursive

https://docs.aws.amazon.com/cli/latest/reference/ssm/get-parameters-by-path.html#synopsis