He is not lying. They have been able to detect and block CFW and Pooled FW since 2022. Firmware developers have been playing with stupid configuration tricks (PORT/header type) which are illegal config spaces that don't exist legitimately on any PC. But it works, and it's able to temporarily get their FW to read while the Valorant process is active. Again, these FW are easily detectable, and the Vanguard team is well aware of them and just uses them to ban waves or block in waves.
Vanguard can perfectly stop any 35T or 75T in the market if not for those dirty tricks being used. Not even Faceit is able to detect or block the pcileech-wifi project
Remember gdoc is just the head of Vanguard. He didn't build this. The real person who built this is Everdox. He even mentions it in this tweet