Hello @raphaeladosanjos and welcome to the community,
You can see my answer to a similar question here
But you are correct once the password is auto-filled into the website it is essentially out of Bitwarden’s ecosystem and control at that point.
Shared credentials really should only be provided to those to whom you have some level of trust already, though what you are looking to accomplish may be capable with the use of different managed browser policies.
It also appears you may be able to perform a registry change to also make this work.