While it is generally legal to bypass a lock on a device you own, doing so on a device you don't own may have legal consequences .

Users who prefer a guided interface and high success rates across various ZTE models. 3. TSM TOOL PRO TSM TOOL PRO

Tools like SamFw FRP Tool actually work on any Qualcomm-based ZTE (like the ZTE Blade Vantage). This is a safe, widely used software.