Attempting to flash TWRP without preparation can result in a "soft brick" (a state where the phone won't turn on properly). Ensure you have the following ready before starting:
For Unisoc SC9863A devices, the bootloader is unlocked via fastboot oem unlock or using a special script. twrp itel vision 1 pro
After flashing, (it will replace TWRP with stock recovery). Instead: Attempting to flash TWRP without preparation can result