homeassistant

A slow reply, but I've recently migrated from a Pi to an ex-business micro form factor PC. It ended up costing about $150. Whichever one and spec you get, the RAM can be upgraded in most instances to 32GB when required, and most have at least one M2 slot.

Check out ServeTheHome on this. If you go for a fairly recent chip, and pick the t-series (lower power), a box with HomeAssistant running in a VM uses less than 10w at the wall most of the time. Not much more than a Pi, and with far more room for expansion.

I went down the VM/Hypervisor route, and would recommend it. It gives a lot more scope for fixing problems, and you can also use it to host other things as needed.