This project is only 500 MW here

https://www.pv-magazine.de/2024/09/20/flexbase-plant-500-megawatt-redox-flow-speicher-in-der-schweiz/

And other places say 800 MW

Both of which are comparable to large hydro.

Modern pumped hydro has a ramp up in the 10s of seconds range.

Anyway. Same ballpark in terms of power.