This is very different from peppering. Salt/pepper is all about server storage/verification. The "path" is plain, hash, salted hash, peppered hash.
Plain:server stores the password, client sends the password - matching is simple. When server is breached, all passwords are known.
Hash:server stores a hash of the password, the type of hash. Client sends the plain password, server hashes and compares. When server is breached, most passwords are known, by way of rainbowtables/brute force.
Salted hash: same as hash, servers additionally stores random salt pr account. Hash is over plain password and hash. When server is compromised, weak/dictionary passwords are compromised via brute force.
Pepered passwords: an additional secret is used for salting. The stored hash now depends on plaintext password, plain salt, "secret" pepper. When server is compromised, most likely pepper is compromised too. If not (eg: only database/backups are exposed), pepper needs to be recovered before brute force of passwords is viable. If the attacker has an account (know a password) it's straightforward to attempt to brute force the pepper, but unless it's weak (eg not a 128 bit random number) - it should not be feasible.
Finally, horcruxing - has nothing to do with server side. Has nothing to do with hashing. Is a simple suffix appended to any given password stored in a password manager, in a INMHO misguided attempt at improved security.
Server sees full password on account creation and login. Seems to suggested to share "horcqrux" cross accounts.
An attacker compromising the passwords stored in the password manager, only gets ~half the password. Need to get the other half via brute force, through compromising another account sharing the same suffix/horcrux, via keyboard logger etc.
A physical compromise of a device with a password manager seem to likely open up for a lot of these attacks.
Note that bitwarden uses 2fa to authenticate a client - but AFAIK if you have a copy of the data/vault - the passphrase is sufficient to get the decryption key.
Horcruxing defends against some odd threats, and otherwise adds more complexity than security IMNHO.