I really like TiKV: can you explain what the issue is with it? And do what are ways to resolve it if TiKV does not resolve it themselves?

Did you do any profiling on your in memory store? I am looking, working on a toy project, for something like this that has 3 layers: local mem, distributed memory and distributed persistence with the same api and, more specifically, query engine. There are kv stores for these (TiKV and Foundation for the last category), Rondb maybe for the in distributed in memory but locally, it should be capable of very high volume (evmap doing a billion/minute but that would not work as not transactional). I bet it is too early to worry about perf for you but it seems you can leave most of that to the kv store which I like.