Yeah you’re definitely in overkill territory but it’s nice to have extra potential in your system for new services or if you want to play around with VMs, containers, etc. What I find is most common for home server setups is that their CPUs are overprovisioned and memory is under provisioned. In a home server context there’s a TON of CPU downtime but a lot of simultaneous services running consuming memory but not really doing much. But I see you’ve got plenty RAM to spare here so if you want to tone down the cost anywhere I’d say the best place is to tone down the CPU.
I do mini PCs and USB hard drives. More frequently accessed stuff and smaller files (think music, pictures, documents, backup repositories) resides in about 6TB of SSD storage. The only way you could go cheaper is probably raspberry pis or something but they’re not nearly as good in terms of compute for the money.