Prius is always dead every winter

Just replaced the hybrid and 12v battery 6 months ago from green bean battery.

Ive gone through atleast 3-4 12v batteries now. Why does my prius suck so bad in winter?

I constantly gotta take out the 12v battery from the back and then charge it.

I regret buying this prius. Maybe I should take it to a mechanic, idk... how can I fix this issue? Am I missing something important?

I just wish the car would work.

Edit: So my new game plan is to follow everyones advice here

1. Get a trickle charger, watch youtube videos
2. Install permanant leads under the hood (i have no idea what this is)
3. Make sure I got no phantom drains like lights, not closing door hard enough, or fuses etc
4. Drive the dang car atleast evey 2 days.

By doing this, I hope I wont need to bring it to a mechanic.