That's true. Last time i tried that with Bitcoin Signet, i got compression ratio 0.63 (505MB / 798MB). For comparison, compression you choose have ratio about 0.81 (397GB / ~486GB).
This took over 2 hours on all CPU cores already.
Does faster drive (something like PCI-e 4.0 NVMe or regular even regular SATA SSD) mean anything in this case or is it only CPU bound? I assume that in this case the CPU and core clock (IPC performance too) is the most important aspect?