Somethings to consider when purchasing a new or used graphics card.
5700XT - Should have warranty if anything happens or stops working. Great card, can handle a lot of newer games with ease, and shouldn't bottleneck your current CPU. (2019 GPU)
1080Ti - About 4 years old, has lot of power and can play just about any game with ease. Could possibly bottleneck your CPU, but depends on the task. However if it gives up, there's no warranty most likely. (2016 GPU)