I have successfully programmed this device using OTA tuya-convert version 2.4.3 (Apr/2021)
Warning! Do not buy this product!
Was able to flash with 5 aligator clips (no soldering) RX/TX/GPIO0 route to PCB edge/pad with labels. Gnd/3.3 and be clipped from pins found between chip and regulator. Need triangle screw heads (torex can work). NOTE however, this product was found to have a hot/neutral reverse issue on the middle and right power outlets. This is a design issue on the PCB itself so not a one-off. Unsafe product should not be purchased!