The hash function used in various aspects of cryptocurrency, such as proof-of-work, signature hash, P2SH/P2WSH/Taproot, and merkle tree, need to be changed in case of a cryptographic break of the SHA-2 function to prevent attacks. However, changing the proof-of-work function is the lowest priority, and pursuing it may be a waste of time. Ultimately, the real world decides, and implementation trumps discussion.