Do you run high refresh rate/high res? Based on meeting your budget I'd go for the 5700xt or 5700. The 2060 super and 2060 are also decent choices but they trade price for Nvidia's proprietary features which is questionable at the budget level. If you want to save some money you can look at the 1660 super/1660ti (whichever is cheaper, they perform similarly). For used options as I believe was said before you can pick up a Vega 56 for around 250, then overclock it and/or flash a Vega64 vbios and/or mess with powerplay modding and get some nice performance.
Keep in mind that even a 1660 is over twice as powerful as your card. At the 350 to 400 dollar price point, the cards are at least triple as powerful. Just depends on how much FPS you need at which resolution.