do not use wifi connection for servers since this will lead to wifi card overheating. always use ethernet
Server grade CPU like AMD EPYC is capable of doing AI inference, and has a massive amount of RAM.
Keep your machine plugged, 24/7, even if it is just a Raspberry Pi.
Many times you face some problem like connection error, program unexpected exits, system freeze etc. Your purpose is to add more features to the system and never let it powered down.
If you cannot afford the power consumption, start with some small server, ramp it up for a long time.
Celeron MiniPC is very cheap. However SSD and large RAM are required for quick response.
You need OCuLink for eGPU connection.
When using smartphones and laptops as server, if no software level charging limit is supported, you need hardware switch controller, controlled by USB or HomeAssistant compatible protocols.