This direction could be confusing especially for people new to OpenStack. The SSH command actually fails because it takes some time until the VM actually gets ready and the SSH service is ready to accept the connection on top of OpenStack.
$ ssh -i /home/ubuntu/snap/openstack/223/sunbeam ubuntu@10.20.20.53
(no response)
^C
$ ssh -v -i /home/ubuntu/snap/openstack/223/sunbeam ubuntu@10.20.20.53
OpenSSH_8.9p1 Ubuntu-3ubuntu0.1, OpenSSL 3.0.2 15 Mar 2022
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to 10.20.20.53 [10.20.20.53] port 22.
debug1: connect to address 10.20.20.53 port 22: Connection refused
ssh: connect to host 10.20.20.53 port 22: Connection refused