No, that is not how it works. It would only turn off the settings and the CSS – but the CSS isn’t working for you anyway, so it is expected that nothing changes.
I really can’t say more. I haven’t seen your site, let alone your ACP, so I can’t check what is going on. You could start fresh and remove SuperGrid entirely. (Note that you would have to manually remove all SuperGrid templates. They are not removed by removing the plugin.)
But it could also be that you have some other issues on your website which just result in the SuperGrid CSS not working. That is in fact very likely. I’ve seen it many times. Because IPS merges the different CSS files, a problem in one file could stop the rest of the additional CSS to fail.