1660ti does 507 H/s with XMR and 30+ MH/s using 60-70 watts for Ethash.
Even if it does that, a rx 570 can be bought for $100 and the 1660ti is around $350. What the hell.
The 1660 is $220.
The 1660ti is $279.
Avoid bullshit variants or paying for markup.
A 2060 is $350.
A P106-100 is around $100 if you are looking for cheap used GPUs.
There isn't a point in mining ETH right now, better off mining another coin and exchanging it into ETH if you want to accumulate it.
If you really only want to mine XMR; sure get an AMD GPU.