The problem with these older units is that we have come so far in terms of performance per watt that the cost of electricity quickly makes them irrelevant.
I used to run a cluster of Dell 710s that I was able to replace with a few M720q very cheaply off eBay and run the same workloads at less than 1/3 the power usage (even better at idle, since that really where these old units don’t do well).
I have seen a few converted into DAS or drawers for a rack, but you’d have to already have a rack for that to be useful or worthwhile.
To me this sounds like you’re missing another service to monitor your internet for uptime. I recommend Uptime-Kuma.
JK. Best part of the self hosted media server is I can usually get away with updating and rebooting the firewall while the wife is watching her shows and she’s never the wiser!