Yeah this is not possible.

btcrecover or any method of brute-forcing your password just tries many different passwords, and it can only get a single success or failure result for each.
I repeat: It is impossible to "recover" one character of the password

The opposite direction works though:
If you remember some letters, maybe a couple, maybe even if you're not sure of their positions, it can help you speed up btcrecover a lot.