Snap Docker service does not auto start container on reboot

I have a pihole server that I installed through docker

And I've installed docker through the snap command

sudo snap install docker

And the service is enabled and auto starts on boot.

qqerqqqr@ubuntu:~$ snap services
Service                         Startup  Current   Notes
docker.dockerd                  enabled  active    -

According to the docker docs as long as the docker daemon is running. A docker created through:

docker run -d --restart unless-stopped pihole

Should auto re-start on boot. However this is not what I observe. Any help would be appreciated.

I am running all of this on an Ubuntu Core machine on a raspberrypi4

I'm using docker to run some services that are containerized with Docker.

to enable the auto-restart of those containers I run this scenario:

first I run my containers without --restart option

docker run -d -P --name PostgreSQL --network module_default_network masterasiyabani_postgresql:dev

then I upgrade my container and add a restart option to it :

docker update --restart=always PostgreSQL 

Now when I power on my system or restart it my container will start automatically.