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Regarding question 1: tuya are well known to implement custom commands in their devices in an apparent effort to stop them working with 3rd party hubs. You only have to look at issues logged for tuya on the herdsman github (open source zigbee stack) One example: https://github.com/Koenkk/zigbee2mqtt/issues/9057 where older versions of the device worked in a standard way and then they changed it. Open source community keeps reverse engineering it like there but typically 3rd party commercial companies wouldn't do that so it would likely not work (properly). Comment from a tuya engineer when one of the guys on that issue asked them for help: