Even pumped hydro is pretty small for seasonal storage.
Probably the only economical approach will be some sort of factobattery[1], which can be thought of as a flow battery which operates "once through" to avoid round-trip losses. Instead of outputting electricity, the beneficiated material itself is the economic output.
This eliminates the entire chemistry-to-electricity side of the process, which may require dissimilar equipment under some approaches.
Probably the only economical approach will be some sort of factobattery[1], which can be thought of as a flow battery which operates "once through" to avoid round-trip losses. Instead of outputting electricity, the beneficiated material itself is the economic output.
This eliminates the entire chemistry-to-electricity side of the process, which may require dissimilar equipment under some approaches.
[1] https://www.moderndescartes.com/essays/factobattery/