Where RDNA really shines is in a custom 5700XT with a good PCB and cooler. Cards like the Red Devil and Nitro+. I still have my 5700XT Nitro+, and it is a great card. Also it is helped by the 256 bit memory bus. Back when ETH mining was big, 5700(XT) cards were some of the best for it, even over their newer RDNA2 successors. This doesn't really matter now, but the 256 bit bus still helps some I suspect.
Last I checked the high end 5700XT cards were going for around $150 or less used, which is a pretty good bargain.