Restore PROD database to QA with AlwaysOn
what are my options to get rid of the old secondary target database?


You can create linked server and use Execute At LinkedServer. This is what I am doing in my current scripts when I have to refresh AG env in Dev / QA from PROD.

You can use powershell, etc .. but Execute At LinkedServer just works fine for my needs.


  anyone has a super hot way to get Production data down to QA or DEV environments easily and automatically?


Refresh scripts to downstream environments are specific to company environment esp. the post restore process like desensitizing or masking data, etc. So, I would say, invest some engineering time and make the process repeatable that will save you a lot of time in future.