disk stuck

Before resorting to brute force, please tell us which iMac. They have been in continuous production since 1998 with different families with literally hundreds of variants. Those families also use different types of optical drives. What you do with a slot-loading drive is very different from a tray-loading drive.

If you are not sure what iMac variant you have, you can use this Apple support page to lookup its specs by serial number if the computer is not too old:

Check Your Service and Support Coverage - Apple Support

If that page does not return a result, then you can use this one:

https://everymac.com/ultimate-mac-lookup/

It seems to work better for older Macs.

BTW, this forum section is for iMacs made between 1998 and 2005. is yours that old?

Thank you. Have you tried restarting the computer while depressing the mouse button?