Either decisions are made using proof of work or they are not.

Bitcoin consensus does not comes about through proof of work [longest chain]
If the nodes and miners reject a block as invalid then it would not persist as the longest chain. If the nodes and miners accept a block and continue to build on top of it, then that chain is Bitcoin.
Proof-of-work both
enforces and
defines the laws of the systems
Proof-of-work exists to order transactions deemed valid by the consensus of rules dictated by the nodes.
For the millionth time it's the longest *valid* chain you disingenuous fuck