I did try to go to object mode select cartridge but it selects the whole console together, yeah I can select the cartridge manually but I can't select every geometry when I am working on a project with a lot of geometry sir.
Can you post more screenshots of the problem? Even better if you can post a screen grab video to see what's going on. If you tried it on object mode and it stills select them together, then perhaps they are not separate. Make sure in edit mode you select the cartridge and P and separate by selection.