iPod nano 3 not working properly. Please help me :(

I bought a used iPod Nano 3 4GB three years ago. It's been experiencing a lot of issues lately. The symptoms are as follows:

1: A white screen appears when waking from sleep mode.

2: While the screen was always on and playing music, the screen would freeze approximately every two hours. When I woke it up from sleep mode, it would sometimes display a white screen, but sometimes it would display the song menu.

3: When I reset the device while it was charging, it initially didn't detect the charger (showing 100% battery). When I unplugged the charger, the battery would drop slightly. When I plugged it back in, it would charge.

4: When I repeatedly pressed the "Sleep" button, the device would freeze after a while. It usually shows a white screen, but it can also freeze differently.

5: Also, the battery icon changes on its own. Sometimes it goes up when low and then drops back to the same level. Sometimes it would turn red, then turn yellow when I put it to sleep and then turn it back on. Sometimes it would even turn green.

These problems don't occur while charging. While charging, it played 85 songs for six hours straight. There were no freezes with the screen always on. While charging, I went into settings, lowered the volume, and navigated through cover flow like a normal iPod, and there were no bugs. I also did this with sleep mode enabled. It didn't freeze at all when I woke it up.

I want to determine if the problem is with the SSD or the battery, because I'll be ordering a new battery accordingly. Please help, thanks :)