Custom recovery tools cannot read Oppo's proprietary encryption. To install a stock ROM via TWRP, the .ozip must first be converted to a standard, "flashable" .zip file.
Obtain the open-source oppo_ozip_decrypt.py script from trusted Android development repositories like GitHub. oppo ozip file flash tool
Use an updated auth bypass utility corresponding to your chipset, or seek official service assistance if the device bootloader is entirely locked down. Error: Device Not Recognized (CMD or Flash Tool hangs) Cause: Missing or corrupt USB interface drivers. oppo ozip file flash tool