I recently found the OpenBeken project after buying a three pack of Globe smart plugs and realizing they use BK7231T's and not esp8266's. Flashing the plugs with OpenBeken is easy enough given its similarity to Tasmota.
I used a pocket knife to pry open the case. Sliding the edge into the seam between the two halves helped break the adhesive hold.
I soldered on just the 3.3V, GND, RX, and TX wires initially but couldn't get uartprogram to connect. I had to add a wire to the CEN pin as well and short it to GND while the uartprogram was "Getting Bus."
After that, a bit of trial and error led me to the following pin configuration:
P7 - LED_n
P24 - Rel
P26 - Btn