Topic and Payload non-platform standard

Topic and Payload non-platform standard

Hola!
I want to work with the following topic and payload:

023-06-28 22:53:27: [MQTT] Device publish {"topic":"Advantech/74FE486BAA2A/data","payload":"{\"s\":7,\"t\":\"2023-06-29T01:53:27Z\",\"q\":192,\"c\":0,\"di1\":false,\"di2\":false,\"do1\":false,\"do2\":false,\"ai1\":0.000,\"ai_st1\":4,\"ai2\":0.000,\"ai_st2\":4}","qos":1,"isHex":false,"bucket":"6499c4e835b04a000efbad2e","messageId":3400}


As the data sent is not in accordance with the MQTT input stream, I am unable to read the variables