I was only trying to point out the apparent effect of randomness that hashes give. Randomness is the key here, since probably no one is going to brute force a unhashed password, since the password would already be known. Not all websites automatically truncate a password, although yes, using the first 'n' letters would be a good idea. Some websites straight up say the password is too long, and you might have to try and guess the limit.
I don't think the algorithm matters here, but only the length.
Horcruxes are similar to what emmanueloga_ has mentioned. Horcruxes were special things in which Harry Potter's lead antagonist, Voldemort stored parts of his 'soul', so that even if he died, someone cpuld revive him using the horcruxes. I haven't kept up with Harry Potter for a year now, so I might be wrong with respect to the exact definition.
Older and weaker hashing algorithms are probably better for this, sha384 and upwards produce large hashes that might be too big for passwords for some websites. Protonmail trims anything more than 72 characters.
See - https://www.reddit.com/r/ProtonMail/comments/khrzhe/pm_ignor...
I don't think the algorithm matters here, but only the length.