I need to check thousands of Bitcoin addresses for balance. The reason I need to do so is because I lost a small part of my written down private key.  I paid an trustable local expert for recovery and made a contract about that for safety. Now I have a list of every possible mutation of my private key and the associated bitcoin address. Somewhere in this list is my lost private key but it‘s quite a lot to check. I‘ve been doing that for days now. I could go back to my local expert but that would be another lot of money that I would have to pay.

I am just a normal bitcoin user with little technical experience. I am not a programmer or something similiar. I know there a many possibiltys with technical experience. Is there a way I can automatically check this whole ton of bitcoin addresses?

I have read a lot about that and people say there is a programm called Bitcoin Core that can do that for me? But how? That‘s the old wallet right?