I would choose 1660 super
Easier to overclock, only memory clock and power limit, 15 minutes you can have your card running
6Gb is enough until early 2024
ETH delayed again the difficulty bomb until July 2022, so there's time to make some money
1660 consumes less power and generate less heat
Just be sure to not overpay the gpu
same
coins have varying lower limit on gpu gb size needed, i'd stick to 6gb+ cards. google "dag size calculator". as a newb that learns quickly, grab a 1660 super. they’re reasonably priced and will get you 30MH/s each.