So i tried that and you can see that the verifying of proxy setup is done correctly but i have the same problem by trying to run hello-world:
$ systemctl show --property=Environment docker
Environment=HTTP_PROXY=http://xxxx:xx/
$ sudo docker run hello-world
Unable to find image ‘hello-world:latest’ locally
docker: Error response from daemon: Get https://registry-1.docker.io/v2/: remote error: tls: hand shake failure.
See ‘docker run --help’.