SHA256, difficulty retargeting algo as well as nation/city-based coin are already out dated

Rebranding is not useful at all for a coingen based coin.

If you have carefully studied HongKetoCoin's source code, you will know that there are inconsistencies, which are the common problems of bitcoin-based coingen coins.

So rebranding is not good enough. You need a clean hard fork to make HKC becoming a really workable one.

Good luck!