Citus is also used for large time-series / analytics use cases e.g. https://www.citusdata.com/customers/heap

There's a question of what you actually want to do with the time-series data. If you don't expect to have much data or just want to store it and maybe occassionally query it, then a single server with partitioning (e.g. through pg_partman, Timescale) might be enough. If you want to build an analytical dashboard that needs to remain fast even if you're dealing with many users and terabytes of data per day, then you probably need Citus.

Citus can load, aggregate and query the data in parallel using all the cores in the cluster. It also supports Postgres' native partitioning and pg_partman: https://www.citusdata.com/blog/2018/01/24/citus-and-pg-partm...