Depending on your workload you might also be able to use Timescale to have very fast analytical queries inside postgres directly. That avoids having to replicate the data altogether.

Note that I work for the company that built timescale (Tiger Data). Clickhouse is cool though, just throwing another option into the ring.

Tbf in terms of speed Clickhouse pulls ahead on most benchmark, unless you want to join a lot with your postgres data directly then you might benefit from having everything in one place. And of course you avoid the sync overhead.