How do I detect what my string is encoded or encrypted with?

Hey HN. Ive been trying to dig up some old crypto and have come across a problem I assume would have some sort of solution but doesn't seem to.

I have discovered a string on an old hard drive of mine that I'm certain relates to a crypto key/wallet of mine. However, after establishing its encoded or encryped I cant seem to find a tool that can give me any hints as to how. I was hoping to find a bip recovery mnemonic for an old blockchain.info wallet or similar.

The string is 88 chars long. Starts with AQAA and is a random assortment of upper, lower and numbers. There is a slash at position 81 and the last character is an asterisk. A tool I found says It's shannon entropy is reported at 4.90 and its apparently UTF-8 valid so that means it's likely not encrypted?

The slash made me think it was base64 but no dice. Any idea if theres a tool that can help identify some clues? Thanks!