Prius C - Ready Light Won't Turn On

2012 Prius C with key ignition - This has been an ongoing issue for almost 2 years. There are times when I only drive the car once a week, sometimes less. The garage where it's parked, is heated. Sometimes, when I try to start the car, the ready light won't come on. When I shift it to drive, it says it's stuck in Park. Here's the thing; I can shut everything off and on the second, sometimes third attempt (Maximum 9 though rare), it starts, the ready light goes back on and everything seems fine. It still drives well.
If I drive the car, turn it off, then role up the windows after the car has been shut off, it will have the same issue. If I drive the car regularly, there's hardly ever an issue. Sometimes it happens if it's parked on a weird slope. Sometimes, I have to get out of the car, and open and close all of the doors, including trunk, get back in, and it starts.
I've read some forums that say it's an issue with the negative terminal attachment to the chasis of the car. Does anyone have any thoughts on this? I've read lots of forums suggesting to replace the battery, only to find out the problem returns a few months later. I think it goes beyond replacing the battery. It's something else.