Quantum attacks on Bitcoin hashing aren’t a real threat for several decades.

Right now, logical qubits run effectively at around 1 kHz. Physical qubits can tick at about 1 MHz, but you lose a lot of that speed because you need many rounds of error correction, and each logical qubit is built from many physical qubits. That makes practical large-scale attacks on Bitcoin’s proof-of-work unrealistic for a long time.

Shor’s algorithm is a different story. It matters more in the next 5–10 years for wallet security, especially for very early coins on the blockchain where public keys have already been exposed. Those coins are more vulnerable once strong quantum computers exist.

People are already working on quantum-safe wallet designs, and there’s at least one Bitcoin improvement proposal that suggests using NIST-approved quantum-resistant cryptography.