To summarize: You're wrong. Existing implementations have not shown that they can beat 128bit encryption. They aren't even close. That's the current situation. I'm not saying that in 5 years we won't have better technology. We might operate with 1400 qubits or be stuck at 140. Nobody really knows.
there are many quote that say otherwise, so no i'm not wrong at all, for a quantum computer brute-forcing a 256 key is like for a normal computer brute-forcing 128 key, it's like dividing by two(the exponent not the number, so is equal to a root square of it), this should be clear, and with that in mind you could deduce easily, that a 128 key for a quantum computer is equal to a 64 key for a modern computer, and a 64 key can be brute-forced with a normal computer(not just one i know, but a very big farm can do it)
just simple logic, you don't need to search for anything to deduce this...