As other comments in this thread, I want to echo the value for money that is to be had in refurbished SFF office PCs that come available on the second-hand market.
I picked up an HP ultradesk something or other for dirt cheap a while back. When I got it it turned out to be surplus stock, so not even second hand - was brand new, for maybe 20% the retail price. Dead quiet, and super power efficient. It's not the most powerful CPU, but it's 10th or 11th generation which is perfect for hardware encoding for my media server use case.
It does not have all the hardware for RAID and multiple hard drives and all that, but one NVME boot disk, and one 16TB spinning rust disk is more than enough for my needs. It's media, so I'm not worried about losing any of it.
These boxes are cheap enough that you can get multiple ones responsible for multiple different things in a single "deployment". At one point I had a box for NAS, a box for media server, a box for my CCTV IP cameras and a box running homeassistant. All humming along nicely. Thankfully I was never masochistic enough to try some kubernetes thing orchestrating all the machines together.
This is all obviously for the homelab/personal use case. Would not recommend this for anything more serious. But these machines just work, and they are bog standard X86 PCs, which removes a lot of the hardware config and incompatibility bullshit associated with more niche platforms.
