In order for
a quantum-computer to pose danger to Bitcoin
it would
require to have between 100000 - 1million logical qubits
. !This kind of quantum-computers not going to exist for the next 20 years for sure.
Anyone else who claim otherwise is an idiot like this guy called Jameson Lopp:
https://bitcointalk.org/index.php?topic=5550298.60
The idiot proposed to BAN all Bitcoin transactions permanently that are not "quantum-resistant" 5 years after activation of his and other "corporate fuckers" BIP.