I decided to search for the original firmware and share it on xda for others who might need it.
The link to the firmware:
Does anyone have TWRP recovery.img for this tanix box?
I've found a twrp flashable zip but it's some sort of liveboot.
I've succesfuly recovered my bricked Tanix TX3 with the USB burning tool.
You need a usb to usb cable, I used my phones usb cable -> usb to usb C cable and my computer had a USB C input/output on the back so that worked for me.