I'd agree with OmegaStarScream here. This looks like a Google 2FA code.
They use 'secret codes' with capital letters + numbers and a length of less than 16 symbols.

This definitely isn't a private key. You need way more characters to encode a private key (256 bit).


Do you remember anything at all regarding the wallet you have used ?
Did you use an online wallet ? Or did you maybe use a desktop wallet ?

This GA code could be from anywhere.