The 2060 will outperform the 1070. In most cases the 2060 will be a better choice. Used 1070s will be generally a bit cheaper than new 2060's, but they're obviously not new anymore. If you're building a new system, I'm going to guess that the 2060 will be a better bang for the buck and will also be more futureproof.
You can also look into a new GTX 1660 Ti. They're a bit cheaper than the RTX 2060, but perform a little less and lacks the ray tracing capabilities.
In your case I'm expecting the GTX 1660 Ti to be the best choice. Unless you specifically want the better performance of the RTX 2060 or the ray tracing capabilities.