I would go for the Wyse 5070 as a server. More RAM is good and the CPUs while somewhat slower are more power efficient.
The 4/5th gen Intel CPUs are the last gen that is really quite poor in power efficiency when mostly idling. 6/7gen made huge improvements in that regard.
Upgrading the storage should be possible quite easily.












At some point the benefit of extra RAM isn’t there anymore compared to what the CPU can actually run. With a CPU like that 8GB is probably sufficient and 16 would be merely nice to have for some additional caching.