But since it's not torn, the rest are still barely visible, yes?

If so, you may be able to minimize the characters to bruteforce by guessing the possible washed-out characters.
Depending on the condition, you may be able to minimize it to a doable difficulty.

For example: a small circular washed-out character could be an 'a', 'o' or 'c'.
Then when bruteforcing the private key, input those as the possible characters of that specific place.
The issue is, I don't know any private key bruteforcing tool that does that so you might have to search for one yourself of find someone to code it for you.

If it's totally unrecognizable, then there's no chance to bruteforce it.