Leaving a LiPo fully charged is perfectly fine provided you store the battery at the same temperature it was charged.

The only danger exists if you were to charge the battery at 72°F and then stored it in a hot space above 100°F then the increase in temperature will cause the voltage to spike and then damage can occur.

Keep in mind that a LiPo stored at 100% charge at room temp will lose 20% capacity over 1 year so plan to replace this battery once a year if you do this:
https://batteryuniversity.com/articl...ased-batteries

If you want the battery to last, then place it in storage mode and only charge it immediately before each use.

Another option is to bring a fresh battery with you when you plam to use the car and never store any batteries with the car.