CPU is def not the bottleneck for chain sync anymore. Seems maybe more of a disk i/o issue. Bitcoin core does this weird dance on load external (blocks already in file) that seems to not efficiently use disk. I seem to have hit a wall of no additional improvement despite upgrading.
Discussion
Probably at a point. For me, Literally using the same drive. The pi is essentially 90-100% cpu when doing the initial sync, new server was maybe 20%.