Overengineering. It's either the young engineer that wants to use the latest trendy technology or the old "architect astronaut" that believes only "enterprise level architecture" can solve all your problems.
Even when I worked in electronic trading and we were dealing with 10 million events/second on combined feeds, we kept our architecture simple. Why? Experienced engineers realized that the more moving parts, there's more things that can go wrong (and it makes it that much harder to pinpoint).
Just time your queries, get a P95, and stream data to an analytics database if you don't want your prod to be exposed to added latency. No need to create some fancy distributed consistent system with caching layers and enormous test harnesses if the analytics workload might change next week.
I'm a huge fan of just creating a separate analytics database you stream prod data to and letting those with SQL knowledge play around there. Surprisingly, they rarely break anything. And if they do, it's not going to take down everything else with it