What do yo mean by high-frequency data? 100Hz, 1KHz, 100KHz? For that kind of use cases many time-series DBs break apart. We have customers storing multiple millions of high frequency measurements per sec in arrays.

I would say, Postgres is not too storage efficient in itself for large amounts of data, especially if you need any sorts of indexes. Timescale basically mitigates that by automatically creating new table in the background ("chunks") and keeping individual tables small.