> Proof-of-work solves that problem by putting the network on a trustworthy clock. It’s a kind of computation which takes a predictable amount of time to run, and which can’t be forged by a bad actor.

That’s not right. PoW takes a completely unpredictable amount of time. It’s not about a clock ticking, it’s about making the presence of two incompatible versions of history as expensive as possible, thus forcing the network into consensus.