If you want the best performance for DaVinci Resolve, the best you can get is NVIDIA GeForce RTX 4090. However, it is not the only good GPU for DaVinci Resolve, Yes, it is the best, but there are some other good ones such as AMD Radeon RX 7900 XTX or GeForce RTX 3080 and 3090. But in case, you want the best of the best, go for  NVIDIA GeForce RTX 4090 24GB.