Sorry but that's not what the OP asked for and I'm not sure why you need to attack him, perhaps you should read his post again. He clearly knows so much more about how this 'hack' works than you.Bro, if they released their private keys to randos like you (or anybody else), I'd immediately stop using this ROM.
Read up on how keys and certificates work.
Back on topic, GPay will work if you clear data from Play Store and G Wallet. But the warning will come back sooner rather than later (EG: it's a workaround, not a fix)
I share his frustration, if we were able to spoof our own fingerprint with this ROM, it's very unlikely they would be banned so quickly, if ever
Perhaps, decompile the APK, learn something and you'll see what is actually going on instead of attacking someone for a request that is not unreasonable.