Depending on the AIB both models come relatively close to 230 Euro's new, even the 2060 Super.
Plus the 2060 has RT cores and is able to use DLSS while the 1660 is stuck with FSR implementation.
If you're looking for a cheap-ish GPU I'd recommend looking into the used marked and start out with a 3060, there is an auction where you can instead buy it outright for 230 near me. It'll last you longer than a 2060 Super and waaay more than a 1660. GPU's barely degrade and the only thing you're missing out on is warranty and maybe some dried up thermal paste but considering how recent-ish the 3000 series still is you should be fine.