Hi,
What is you level of electronic knowledge please?
The answer to is it “bricked”, is thankfully NO, but without a way to connect over the WLAN network, it likely can only be re-flashed via the serial programming pins on the ESP8266 - many designs have these as a row of internal pins on the PCB to allow flashing in the factory.
I’ve flashed many, many, devices with Tasmota, ESPhome, Arduino, etc but the first few can be frustrating needing research to trace the micro-controller, pin-out, programming and serial pins, before a few attempts at flashing. It is possible, and persistence does work.
A good resource is Blakadder’s website - it has both device reverse engineering images, and chip pinouts so you can trace others:
For this type of device, I’d probably solder on temporary jumper wires (Vcc, GND, RX, TX, GPIO0) and experiment with swapping RX/TX and reset until a console appeared.
Worse case, you could work out what GPIO pins operate the device, and replace the microcontroller but as you already have loaded Tasmota/ESPhome once, it should be possible again.
If this helps, 
this post!