Q: Car grinds, wont start has a new battery that is now dead from sitting autozone said starter is ok and I turned the flywheel

Ive had my car for 10 months and got a lot of things fixed when I bought it. Ever since I had it I would have trouble starting it like I would turn the key and the power came on but it would make a single click. Id go to start it again and it starts right up, the problem became more frequent over time.. I had a dead battery a few months ago and replaced it, about a week after that I go to start my car and it grinds like really loud. I try starting it again and it grinds, I try a third time and it starts fine. The day after that it wouldn't start at all.. It would just grind. And now its January and its been sitting since early November, since then my new battery is dead and wont charge and I have turned my flywheel and had autozone check my starter and they said it was good but I took it out and connected it to the battery and the spindle only disburts and doesnt spin.. The teeth on the spindle are obviously worn and the solenoid seems to be lose or bad.. Someone please help

My car has 140000 miles.
My car has an automatic transmission.