Please follow the below template, it will help us to help you!
Expected Behaviour:
I wish to log in via command line.
Actual Behaviour:
I used to be able to log in, but the connection is refused now. The Pi Hole is working fine, and I can log into the web admin portal. But no command line, and so I'm not sure how I can update the Pi going forward.
Ssh: connect to host 192.168.1.xyz port 22: Connection refused
That is a network/OS level issue, not related to Pi-hole nor DNS.
Perhaps ssh wasn't configured correctly, or your firewall on the device is not allowing inbound port 22.
You'd have to consult your OS's documentation for further details.