I started with your tier 3 and moved down to tier 2 because of power costs. I work for an MSP, so I have essentially infinite free last gen hardware from the ecycling pile, but the power consumption was too high. I’m in the process of moving from a Dell 720 rackmount to an HP EliteDesk 800 G5-SFF with 32 gigs of RAM that I put a pair of 4TB drives into, plus the 1TB on-baord NVME. Once I finish this migration I should save on the order of 250 watts, or 6 kWh per day, for a savings of about $40/mo in electricity. It’s worth taking your electric rate into account when you size your hardware, and figure out how long your ROI is for that decision.

For storage, I have a 16-bay rackmount server chassis for my NAS with 8TB drives (see MSP comment above) so I don’t have a good suggestion for consumer-grade hardware there. I know 16 spinning drives are pricey power-wise, but I just can’t give up 100+ TB. I’m pondering adding another DAS shelf to grow the array even further, though that will eat a bunch of the power savings moving off of the 720. For the time being, the inertia of not ordering a PowerVault enclosure is saving me money,