First things, you plan own goals definitely a good strategy for maximizing profits. It allows you to diversify your mining efforts and potentially earn more from multiple sources.

Maybe, as for how good the GTX 1660 Super is for multiple coin mining, I suggest doing some research on the specific coins you're interested in mining and seeing if they are compatible with the card.

Generally, different coins have different mining requirements and some may be better suited for certain graphics cards than others.

Finally, if you have got a great opportunity with the GTX 1660 Super at such a low price point. With some research and careful planning, you could definitely make a good profit from mining multiple coins on these cards.