Custom component for IR transmitter

Background:
I have created a universal infra-red transmitter based on an ESP8266, for controlling the televisions and audio equipment around my home. It (or multiples of them) connects to my WiFi network and receives MQTT messages (in JSON format) containing the device to control and required function to execute. The device and function is looked-up in a file stored in SPIFFS and the corresponding codes are then transmitted via the infra-red LED. Currently, control is in the form of a remote control keyboard in a Node-Red dashboard and works very well.

Intention:
Currently, I have Google assistant successfully working with my existing lights and switches in Home Assistant and what I would ultimately like to do is issue the (TV) device and function commands to Google assistant, and have them returned as MQTT packets that can be sent to the ESP8266’s.

Is there a device/component/integration that has, or can be configured to have the custom parameters “Device”, “Function” and “Value” that Google assistant would be able to link to? If Google assistant can pass a value of “ON” or “OFF” to “Patio Light”, then surely it must be able to pass “Volume Up” to “LoungeTV” through a HA component? If not existing, is it possible to develop such a custom component using existing tools?