My iMac G3 DV SE is not powering on after trying to force CD eject

A friend gifted me this iMac a couple of days. It had MacOS 9 and I wanted to update to 10 and also erase the data, but when I tried to boot from a USB the Mac didn’t recognise it, so I got a DVD to burn and put it in the Mac but it wasn’t appearing, so I tried to eject it but it said it couldn’t eject the drive. I search and I saw in an Apple forum that you could shutdown the computer while pressing left button of the mouse and turn it on while holding but it didn’t work, so I continued searching and I found that the hole next to the CD reader you could put the tool you use to eject the SIM at the iPhone, so I tried but it didn’t work. I wanted to try out another time to force eject from the OS but when I turned on the button turned on orange, in an Apple forum said that I should reset the PMU by pressing a button on the motherboard I did and now it powers on and shutdown immediately.

Also I read that it could be the battery but I don’t think this could be it has to be related with the disc.

Is there a solution without doing a hardware repair?

Do you think it could be the battery?

How could the iMac not turn on trying to eject the drive ?

Does that hole used for other things than ejecting the drive?

Thanks for your time and your answers!