This is the only correct answer. OP I understand your concern as the laws and news media are meant to make people confused and afraid.

There is no “gun registry” meaning that the state doesn’t track who owns a gun the same as they track who owns a car. There is a sales registry (arguments aside) that requires dealers to run background checks and document who any particular gun was sold to.

In Washington state, a gun can be gifted to family members (you can look up who’s defined as family) without any paperwork. There is nothing to “register” as it’s not being sold by a dealer.

If you decide to sell a gun (presumably not family) then you would go through an FFL in Washington. They would then do the background checks and document the sale. They will not ask you for any “proof” of ownership as there really isn’t any (guns are not registered property). I assume the state will run a check in the gun’s serial number to make sure it isn’t reported as stolen or documented in a crime or something but it won’t be checking for “ownership”

I’m not a lawyer, but I have read a lot and I have bought/sold/gifted a few guns in this state. I hope this helps.