psmqtt VS MQTT-Explorer

Have a look at https://github.com/eschava/psmqtt

Quote from MQTT Explorer

Sounds like you're on a good path tracking the problem to aws, not the esp. First of all, I'd try to make it work with a "proven" solution, then move on to your own implementation. I have had good success using http://mqtt-explorer.com/ on windows to diagnose a similar situation. Mqtt explorer gives you very granular control over endpoints and topics, so might be helpful to you too.

I would suggest using Mqtt explorer (http://mqtt-explorer.com/) to see how often the sensor updates its values. This as a first step to narrow down the problem.

Here are a few alternatives: http://mqtt-explorer.com/ https://mqttx.app/

Use MQTT Explorer to view and generate messages: http://mqtt-explorer.com/

For MQTT debugging, I like MQTT explorer

You can write test programs to send very specific messages to simulate errors, or simulate entire components that aren't written yet. There are also free programs like MQTT Explorer that will let you browse the message traffic, generate messages manually, log whatever you cant, and even graph your values if you happen to send numerical values (that is really cool when you do some long-term testing).

To use a local server can let you control all details of your full messaging chain. Try other clients can make you away from the ill behaviors or bugs of specific client. I recently demonstrate how easy a free MQTT client (MQTT explorer) send to a free MQTT database on Windows 10 in my video.

A useful tool is MQTT Explorer. You can connect to your broker and see what changes when you use the light through an app or switch or whatever. This should help you understand the manner in which the light talks with mqtt. Once you think you have understood it, you can use explorer to publish test messages to see if it works as desired.