I will note before the rest of my answer: I don't think the earlier question you linked is a good challenge, though it is significantly more clear than the version of your challenge that was closed.
Your challenge remains slightly unclear, but at this point I would call it "not so unclear that it would be closed if originally posted in this format". The biggest remaining problem is that the actual challenge is this:
Generate secp256k1 ecc public/private key pair; hash the public key string through keccak256; the last byte should be 0
but that information is buried and interwoven with a lot of stuff about Ethereum which, by PPCG stanards, is equivalent to "creative backstory". Making a creative backstory is a somewhat divisive topic in my experience, but the less controversial part is that the motivating backstory should be short and separated so that uninterested parties can simply ignore it. The fact that Ethereum is a real thing doesn't keep it from being a backstory essentially irrelevant to what is actually required to complete the challenge, so ideally all the stuff about Ethereum should fit in about the space of your first two paragraphs and everything else should focus solely on making the challenge itself (those three requirements I have quoted) more clear.
As for whether it should be reopened, I think it can be... but I also think it will remain downvoted and likely ignored either way. "Run stuff through a hashing algorithm until the last byte is zero" sounds really boring to me, and because of the requirements for using specific hashing/key generating algorithms any answer other than "find a library that offers the functions I need, my submission is in 'language w/ library' and consists of calls to that library" will require incredibly tedious re-implementation of hashing functions. It also suffers from being abnormally difficult to evaluate whether answers are correct; even assuming an answer can run on TIO reliably, I would need to go somewhere else to retrieve the public key from the private one, and then hash that private key, and then check that it both matches the one output by the answer and that it ends with 0.
Now, does this mean blockchain questions are "bad"? Well... there's a high chance. I can't claim to be an expert, but blockchains by design involve very large random numbers with special properties, and I personally don't think challenges about very large random numbers with special properties are going to be interesting. The earlier challenge you linked gets around that particular difficulty by supplying those numbers, but I have different issues with it. An example of a good Ethereum-themed challenge might be "given a list of transactions, output everyone's final balance" or something similar, but I suspect a "track balance over transactions" challenge already exists and Ethereum-theming won't keep it from being a duplicate.
TL;DR: I've voted to reopen. In accordance with prior consensus a bad but clear challenge should not remain "closed as unclear".
