old servers or servers in general have significant power drain + are generally loud as they are designed to sit in datacenters

a good compromise might be some of the workstation models, they run quieter but still use a lot of power

as suggested by others look at alternatives to nuc that you could get cheaper, possibly with two ssds.

Not a horrible option is also refurbished laptop, you can usually get tons of thinkpads that businesses cycle out, gives you silent run&built in ups