Power on and off relay will work by default with TuyaMCU module.
TuyaMCU 11,1

This is the extent of Kogan/Tuyas 3rd party integration. Google assistant, HA etc. integration treated the kettle like a switch. Current temperature and keep warm settings are only available in Kogan/Tuya app.

Keep Warm

TuyaSend4 102,0 Keepwarm off TuyaSend4 102,1 Keepwarm 40c
TuyaSend4 102,2 Keepwarm 50c
TuyaSend4 102,3 Keepwarm 60c
TuyaSend4 102,4 Keepwarm 80c (yes, 70c is skipped)
TuyaSend4 102,5 Keepwarm 90c

Temperature

DpId5

55AA00 07 0008 05 02 0004 00000063 7C

‘00000063’ is the current temp in hex.

DpType2Id5

Returns the current temp in Deg C.

setoption66 1 to publish all Tuyareceived data to topic.

Home assitant MQTT Temperature sensor

  - platform: mqtt
    name: "Kogan Temperature"
    state_topic: Kogan/tele/RESULT
    value_template: >
      {% if 5 == value_json.TuyaReceived.DpId %}
         {{ value_json.TuyaReceived.DpIdData | int(base=16) }}
      {% else %}
        {{ states('sensor.kogan_temperature') }}
      {% endif %}
    unit_of_measurement: '°C'

### Idle
DpId103    
Data: 55AA00070005670400010077   
DpIdData can be 1 or 0.   
Not sure why its type4    

### Other
dpId1 frames   
CmndData: 01010001 00 0502000400000029 6501000100 6604000100 6704000100

00 - state
050200040000002965 - DpId5 CmndData
6501000100 - DpId101? unused? can't change value. Never found a 101 frame or seen it set to 1. 
6604000100 - DpId102 CmndData
6704000101 - DpId103 CmndData

OpenHAB Setup

Create mqtt brige in ui named openhab (mdrr:bridge:openhab)

Create thing using text config in correct place.

  Thing mqtt:topic:Kettle "Kettle in Kitchen" (mqtt:broker:openhab) @ "Kitchen" [ availabilityTopic ="tele/Kettle/LWT", payloadAvailable ="Online", payloadNotAvailable ="Offline"] {
  Channels:
      Type switch : PowerSwitch  [ stateTopic ="stat/Kettle/POWER", commandTopic ="cmnd/Kettle/POWER", on="ON", off="OFF"]
      Type string : WarmMode [ commandTopic ="cmnd/Kettle/TuyaSend4"]
      Type number : temperature "Temperature [%.0f °C]" [ stateTopic ="stat/Kettle/TEMPERATURE" ]
        }

##Tasmota setup enter into console on tasmota setoption 4 1 setoption 66 1 rule1 ON TuyaReceived#DpType2Id5 DO Publish stat/%topic%/TEMPERATURE %value% ENDON

Link to forup post