I'll tell you this: The RX 6500 XT, which has over three times the theoretical compute power of the APU in a Steam Deck, is almost entirely incapable of providing a decent gaming experience with complex ray tracing. Minecraft RTX? It gets 17 fps at minimum settings and 1080p. Minecraft ought to be less complex than Portal, so yeah, it's going to be rough. Granted, 1280x800 is half as many pixels as 1920x1080, so maybe a 6500 XT will manage 1280x800 at 30 fps in Minecraft. But again, that's 16 CUs, 16 Ray Accelerators, and clocks of ~2.8GHz. The Steam Deck is 8 CUs, 8 Ray Accelerators, and clocks of up to 1.6GHz. So less than 1/3 the performance of an RX 6500 XT, and real-world GPU clocks are probably going to be more like 1.3GHz (due to throttling to keep power use in check).