But bitcoin security has been designed to address the threats that Quantum Computers might pose.
Bitcoin uses Post-Quantum Encryption Technologies, such as Lattice-based cryptography or Hash-based cryptography.
Bitcoin also uses the ECDSA cryptographic security with a 256-bit size.
https://en.wikipedia.org/wiki/Lattice-based_cryptography
https://en.wikipedia.org/wiki/Hash-based_cryptography
Speculation that Bitcoin can be recovered when keys are lost is just nonsense.
There will be no such technology today or for the next few decades.
If that happens the bitcoin system will collapse.
and the replacement for blockchain is just bullshit as well, Blockchain is still the best ledger technology and many use blockchain as an Example of another ledger development.