The first thing I would start with is to disconnect the whole thing from the 230V mains and supply power (AFTER DISCONNECTING FROM THE NETWORK) from a good source of 3.3V to the GND and VDD pins from TYWE3L. This 3.3V must be able to provide adequate current, so do not take it e.g. the output of a USB to UART converter.

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If the hardware then appears in the application, you can suspect that there is something wrong with the power supply. In the opposite situation, the WiFi module itself is to blame, maybe something software is broken.
The TYWE3L is simply an ESP8266, so you can simply connect a USB to UART converter to it, connect GPIO0 to ground and read the flash. Make a copy of the 2MB batch and try uploading Tasmota, maybe with Tasmota this flash will work. It's hard to determine what's at fault for now. Of course Tasmota is not Tuya, but at least you will revive the hardware....