Timeseries is the data model and that is, for the upper end, synonymous with column-oriented. In my top comment, I mean timeseries/column-oriented (there are other series besiudes time, byt they fit the same data model).
The top TS databases are more than just storage too. You need a query language that can exploit the ordering column-oriented gives you that the row-oriented relational doesn't.
On the lower end (eg, Timescale db) trying to fit a timeseries model on a row-oriented architecture which is a poor fit.
