If you only know 1 character this will take years before you can recover the wallet since you said it has 30+ characters which are impossible to recover or I think you will need to run a BTCrecovery for years or maybe decades.

If you just bought the wallet.dat from someone else and the password is more than 5 characters missing then it's hard to brute force even 3 missing characters is not easy to brute force unless if you have a good RIG for brute-forcing.

And another thing is that if you bought this wallet file you are most likely scammed because most of the wallet file out there are free that you can find somewhere here in the forum or other blog posts.