Not if the password is hashed, as it should be. Unless the schema somehow indicates that it uses a hash algorithm such as bcrypt that has a maximum password length. And even then, if they pre-hash the password, the password itself could have more entropy than that. And if there is a maximum password length, then you can probably figure that out via other means, like it being listed in the requirements when you set your password. It does tell you the size of the hash of the password, but if the maximum entropy is sufficiently high, as it should be, then it doesn't really matter; it would still be impractical to brute force.

> there is no company worth its salt that would share DB schema

So you are saying that every company with a self-hosted or open source product that uses a database isn't worth their salt? If your DB is running on a customer's infrastructure, that customer will by necessity have access to the schema. And likewise if the source code for a product is publicly available it is trivial to determine the schema.