I can change my own password (credentials) in the console, but as an admin I cannot reset it for a lambda user.
I've been deleting and reading the user so far, but that's not optimal since the uid changes. Unfortunately our Prod console has not access to ldap so we have to use the built-in authentication for now.
Please submit a ticket for this feature as you are correct, it does not exist.
In the meantime another idea for maybe helping you out a bit would be to interact with the database directly:
table is db_user_credentials
column is oneWayHashPassword
You could create a (temporary) user (using the console) with a password that you know: ex: "resetMyPassword"
Then query the db to see what oneWayHash("resetMyPassword") is...
Then whenever you need to reset a user credential simply update the db_user_credentials table with this one way hash and tell the user that they need to change their password from: "resetMyPassword" to whatever they want.