Will be interesting to see the benchmarks!
There's a lot of KV engines that uses RocksDB now, like CockroachDB (Forked into PebbleDB though), YugabyteDB and TiDB.
Those are all many times slower than Redis though, so having a middle-ground aimed to be similar to Redis, that doesn't eat all RAM, is very exciting!
Isn't TiDB built on top of TiKV?[0]