Different Minimum Level Logs Serilog

The setting you’re looking for is restrictedToMinimumLevel. This GitHub issue shows some examples of this, but for your example, you just need to add restrictedToMinimumLevel to your Args for RollingFile:

"Serilog": {
    "Using": [ "Serilog.Sinks.Console" ],
    "MinimumLevel": "Debug",
    "WriteTo": [
      {
        "Name": "RollingFile",
        "IsJson": true,
        "Args": {
          "pathFormat": "C:\\Logs\\Log-{Hour}.json",
          "formatter": "Serilog.Formatting.Json.JsonFormatter, Serilog",
          "restrictedToMinimumLevel": "Warning"
        }
      },
      {
        "Name": "Console"
      }
    ]
  },