Not able to set a github environment variable in github actions - github

Question

My workflow is using a windows runner.
The workflow runs an aws cli command to get instance IDs. I then try to set the returned IDs as a github environment variable to use in future steps
Here is the snippet from my workflow file:
- name: Get IDs
id: get_instances
run: |
$getinfo = aws ec2 describe-instances --filters 'Name=tag:Name,Values=project-bell' --output text --query 'Reservations[*].Instances[*].InstanceId' --region "eu-west-1"
$instances = ($getinfo -Join " ")
echo $instances
echo "INSTANCE_ID=$instances" >> $GITHUB_ENV
- name: Print IDs
run: |
echo {{ env.INSTANCE_ID }}
echo "{{ env.INSTANCE_ID }}"
So the 1st line in my run command of the "Get IDs" step returns the IDs as an array. So $getinfo looks like this:
instanceID 1
instanceID 2
2nd line I use -Join command to get the IDs to be returned in a single line: instanceID 1 instanceID 2
I then try and set this single line as a github environment variable but it isn's working and not sure why.
When i echo $instances i can see that the -Join command has worked and i see the IDs printed as a single line instanceID 1 instanceID 2.
But on the "Print IDs" step {{ env.INSTANCE_ID }} is returned rather than the instanceID 1 instanceID 2 which i tried to set as a github environment variable in the previous step.
Notes:
I have to 2 echos on the "Print IDs" job as i was just testing if i needed quotations for it to work"
I have the -join command because when i tried to set $getinfo (1st run command) as a github env var i got an error saying it was an array
Question
Am I writing the command wrong to set github env?
Or is it something to do with the values themselves - like does it need to be a string?