It seems that render dragon abandoned the distribution of rendering between CPU and GPU (As was the case pre-RD) and just went "if your GPU can do it, it will, and if your GPU can't, then your CPU will", but those metrics are useless because some GPUs are good but not that good, and no CPUs are even close to that good. Because of this, I get lag on even just the main title screen, as well as in game, on my laptop with an Ryzen 3500U (+Vega 8 Graphics, which can run 48 chunks-pre-RD with 80% GPU and now runs at 100% GPU regardless of render)

This is the opposite issue MCPE-97408, where rather than pushing all rendering to the GPU as reported here, it's pushed to the CPU.