A 460 watt power supply does not leave a lot of headroom, but you do have some options. The first thing that comes to my mind is the
RTX 2060. It isn't a massive leap when moving from the 1660Ti to the RTX 2060, but you can usually find them for around 200 bucks and it will perform better than your current card. Expect 10-20% improvement. You may know the RTX 2060 recommends at least a 500 watt PSU, but you can run the card of something lower. Under extreme load it draws less that 200 watts, so your current power supply should be fine, assuming it is a quality unit. If you want a higher performance jump, the next card I would suggest would be the
RX 6700XT. You can find this video card for 300-400 dollars and it will be a massive jump from your current card. The 6700XT is rated for 300 watts, so you would be cutting it extremely close. If you wanted that card, I would upgrade the power supply as well. For around 100 bucks you can get an
extremely solid PSU that will not only provide more headroom for a better graphics card, but for other component upgrades as well. If you build a new system in the future, you could potentially reuse the power supply later down the line. Hope this helped, take care.