what I am going to say is purely theoretical, as I have never tried to brute force private keys.

I don´t think you will have any success doing this.
If you have enough hash power, you would probably make more money working as an honest node, mining.

Bitcoin protocol is secure enough. If it were brute force-able, bitcoin wouldn't be worth anything.

What i think you could do is to find a collision. If someone made an insecure private key, by just hashing some passphrase... maybe you could have some luck. I tried to do this once, but never found anything. I tried those terms like "wallet" "bitcoin". I found some addresses which used to have balances, but not anymore. But I was doing manually, like 1 address/3 minutes lol

If you could somehow at the same time check if any of those 9.4 million keys/sec have any balance in btc/bch/btg etc...

But I don't think any of that will work, and will be a waste of time and resources.