If you are running on free electricity like me you don't need to worry if bear market will come or not, people tend to sell their GPUS when bears comes because they can't keep up with electricity bills, ROI will take longer than expected is all but will eventually happen
Free electricity or not, to get ROI you need to have a small initial investment. Most people are forgetting but with 30MHS back in the bear market pulled in about $0.25 per day of profit. So even if you got free electricity, if you spent $500 on a GPU (lets say $400 for GPU and rest for cpu/motherboard/psu/ram) you would need to mine 2000 days. Which is around 5 years. Most likely by then ETH will be fully POS and you won't be able to mine it even at $0.25 a day.
$430 for an 1660Ti is a little overpriced because these retailed for slightly under $300 when new. And I think they were going for $150-175 on Craiglist a few months back before this ETH price explosion started. So say $430-$150= $280. So as long as the OP makes close to $300, he should be at ROI.