The bottleneck here is unfortunately the current version of Hand2Note which doesn't handle large databases very well regardless of your system configuration. It's recommended to import hands and build stats in small portions to avoid overloading and freezing the software. It's a known issue and it will be fully reworked in Hand2Note 4.
As for system requirements, yes, during stat building H2N uses RAM mostly, but 16Gb should be fine. However another issue to point out, the current version of H2N is not optimized for multi-threaded workload, therefore Ryzen CPUs with high core count won't perform to the full spec.