You can pass parameters using

dbx launch --parameters

If you want to define it in the deployment template please try to follow exactly databricks API 2.1 schema https://docs.databricks.com/dev-tools/api/latest/jobs.html#operation/JobsCreate (for example parameters are inside a task, there is task array, both are missing in your json)

{
    "default": {
        "jobs": [
          {
          "name": "A multitask job",
          "tasks": [
            {"task_key": "Sessionize",
             "description": "Extracts session data from events",
             "depends_on": [ ]
             "spark_python_task": {
                "python_file": "com.databricks.Sessionize",
                "parameters": ["--data",  "dbfs:/path/to/data.json"]
              }
         ]
....