The most reliable methods for bypassing T2 locks have historically been tethered and rely on low-level bootROM exploits. It is vital to keep the system software on an older version for compatibility.
Press and hold the power button for 10 seconds. Some "locks" are actually sleep/wake glitches. Macbook T2 Bypass Free
There are open-source tools (often found on GitHub) that automate the checkm8 process. While the software is free, the requirement is high: The most reliable methods for bypassing T2 locks
These methods require the Mac to be downgraded to specific older versions of macOS/iBridgeOS. Macbook T2 Bypass Free
Since the T2 chip is based on the A10 processor architecture, it is vulnerable to the checkm8 exploit.