I’m still running a DS414 filled with WD Red drives. I’ve only swapped out one of the drives as it was starting to have issues. I’ve considered upgrading for more features (Docker, Home Assistant etc) but can’t justify the expense just for “nice to have” instead of “need”. Realistically it only stores Linux ISOs that I get with Download Station.
There’s at least one YT channel that keeps popping up in my recommendations that focuses on “Tofu dregs”. All infrastructure, not just residential buildings.