Hello, havent played poker for a long time and decided to come back and play 0.55 thru 2.20 mtts turbo and regular

I wonder what would be the pushing all in range with how many big blinds (like AT+ at 10 at turbos IE)

Ive been very nit and been usually getting close to or on itm but I find myself always short stacked

Aside from the pushing range how could I improve my game?