@Felicity_Tide, I just do not know what to explain again

. I hope he will understand what I mean and the reason I said his suggestion of a cold wallet is off-topic. I am out of merit, I will send when I have enough.
You seem to forget that we currently do not have quantum computers powerful enough to brute force the public keys of a cold wallet to get the private keys. The current quantum computers we have now lacks the required qubit count, coherence time and the power to perform such a complex calculation.
It'll only take quantum computers with the IBM's 1,121 superconducting qubit processor to perform such a task as this is the only way to unlock the full power of quantum computing, and mate I don't think we have such computing power right now.
You quoted the image that the OP posted:
Best Storage Method for Bitcoin in a Post-Quantum World.
The post-quantum world refers to a future era in which quantum computers are powerful enough to break current cryptographic systems.