Hi again, there is a folder called Realtek in Windows x86 folder. I think this is the software necessary, but without installer will dont work. Anyway i’ll send it to you.
https://1drv.ms/u/s!Aic60r9_y_aDg0zyvg8IItue5V5X
Perhaps you can download the original windows from teclast.com/en/firmware, put your model a6c7 in the box.
Or you can uninstall bluetooth in device manager, restart and reinstall, perhaps windows install the correct driver for you.
Another alternative is try installing other uart driver for windows 10
https://downloadcenter.intel.com/download/25070/Bluetooth-Realtek-Bluetooth-UART-Bus-Driver-for-Windows-10