There are a couple options to make this work automatically, but they require some scripting.
Sequential schedules allow you to source content from a search query in the YAML file, which you could update in a single place, either manually or from a script. See https://ersatztv.org/docs/scheduling/sequential/
Also, scripted schedules in the latest develop build let you add content in a similar way, using your language of choice (ETV provides an OpenAPI definition to generate the API client that can be used for scheduling).
Happy to help with either option.