@Corensia
You simply can not make conclusion from total alignment time, because that process consist from 4 subtask and each subtask utilizes differently cpu and gpu:
-detecting. points: one CPU core at 100%, just few %gpu
-generic preselection: 20-50% cpu, 50% gpu usage
-matching points: cpu 40%, ~50%-100% gpu
-estimating camera location - 100% CPU multicore utilisation, GPU utilization 0%
Main difference between those two CPU is, that ryzen 5600x has higher IPC than 9900K, but sadly has 2 cores less.
Dense cloud generation also consist of two subtask, first make sense only compute on GPU(depthmap generation) with CPU set to not use in preferences, and the second is CPU pure only, because it can not utilize GPU at all.(threadrippers will love this second phase)
Just measure each subtask individually and then you will know exactly, if the time differences are cause by LHR or not.