What is the best AM4 CPU for AMD GPUs today?

I’m looking to squeeze the final bit of life out of my AM4 build and finally upgrade from my old Ryzen 5 3600. Since I’m running an RX 6800 XT, I really want to take full advantage of Smart Access Memory (SAM) to boost my gaming performance. I’ve been torn between the productivity power of the 5900X and the legendary gaming reputation of the 5800X3D, but I’m worried about heat and whether my B450 board can handle the top-tier chips. Is the X3D cache still the king for AMD-heavy setups, or should I consider something newer like the 5700X3D for better value? Which AM4 chip pairs most efficiently with an AMD GPU for 1440p gaming right now?