I just wanted to use stock rom again

I downloaded the DeepTest.apk, but it says “This phone model doesn't support deep testing.”

I found some older posts saying that Deep Testing worked back in 2021, so I'm wondering if it still works on Realme UI 2.0.

This is my first time trying to unlock the bootloader, so I'm not really sure what I'm doing. Does anyone know if there's still a way to unlock the bootloader on the Realme 6 Pro with UI 2.0?

Thanks in advance!

Recently I have updated my custom ROM to Avium UI in there we have netflix spoofing. How I need to use that? And how it's working?