I am having troubles with target-mysql creating a to small varchar column. In the code I saw it is based on maxLength in the catalog schema. So I add

schema:
      "*":
        "*":
          type: ["string", "null"]
          maxLength: 65535

To my meltano.yml. Except this transforms every attribute to a string. I would just like to add the maxLength to attributes of type 'string'. Is that possible?

Unfortunately not possible, so you'd need to explicitly add the schema override for each of the string fields. Do log a feature request if you can.