Setup for always on assistant

I have a dual 3090 rig that I use as coding assistant and while it works, it draws a lot of electricity.

Now I want to add another rig that I can keep on all the time, or maybe a vps if that is suitable. This rig should run an assistant model that should be fairly intelligent but doesn't have to be so coding focused. It should basically be like a chat gpt replacement. I'm not sure if something like openclaw/hermes would be suitable for this.

Since it will be one all the time, power usage should be low. What kind of rig and model would you select for such an assistant?