Which regional pass is suitable?

Hi, I planning to travel from Kansai Airport to Kusatsu Onsen on the day I reach Osaka then from Kusatsu Onsen to Ikebukuro/Tokyo after a night stay there.
Seems like the journey will need to use shinkansen.
May I know which 3 days regional pass will cover for the trip? And is it worth for the journey or there will be other cheaper options?

Thank you