Add an offset to a monitored condition without creating additional sensors?

I’m using a bluetooth temperature sensor from Xiaomi and have configured the sensor as described.

   - platform: mitemp_bt
    name: Hygrothermo_1
    mac: '44:66:AA:DD:FF:DD'
    scan_interval: 60
      - temperature
      - humidity
      - battery

I would like to correct the i.e. humidity with an offset of +3%.

I know how to handle this by creating a new sensor via sensor template:

        friendly_name: "corr. Hygrothermo 1 Humidity"
        unit_of_measurement: '%'
        value_template: "{{ states('sensor.hygrothermo_1_humidity') | float + 3.0 }}"

But this method results in additional sensor(s).
Is it possible, to directly correct the sensors value themselves without creating additional sensors?