Ask HN: Time Series Database?

I'm curious what other HNers are using for their timeseries data needs. At my company, we're specifically working in IoT with hundreds of thousands of sensors cumulatively sending in ~5k observations per second (~5 TB of uncompressed data on disk). We've tried all sorts of options and currently are using TimescaleDB, but are thus far very unsatisfied with query speeds (typically, we just want to see hourly averages over the course of some arbitrary time period for a few sensors, but sadly this can take several minutes for just 3 sensors over the period of a year, as an example). As the data has grown in size over the years, experimenting with new options has become more and more burdensome, so I figured I'd poll the crowd to see what approaches are working for others.