You can also buy mainboards[1] and expansion cards[2] (usb-c, hdmi etc.) from the same website. Depending on how beefy of a computer you want there are mainboards from 299 USD to 700 USD. So for ~500 USD you can get a very powerful tiny-ish computer. It obviously won't have the IO capabilities of pi-like hobby boards but it'll function great as a thin client for running linux / home automation stuff.

[1]: https://frame.work/marketplace/mainboards [2]: https://frame.work/marketplace/expansion-cards