My largest speed upgrade so far has been a Optane 905p SSD for AC VM. Really fast random, queue depth 1 access (great for SQL hence AC). $340-399 for 1 Tb while they last.
It's not in a raid and running in a PCIe U.2 adapter card so definitely not official "enterprise". But, I keep good daily AC backups and have a hot-spare server.
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