Sand a flat to create a D profile and then use a shaft collar and set screw

I keep the printer in the room the cat isn’t allowed in

Could you suggest a couple SBC alternatives that I can look at? Currently using some Pi3s and Pi4s for some projects and interested in what I could switch to. I’m not using the GPIO or Pi camera, I am using USB, Ethernet, Wi-Fi, and like the size, price, low power draw, and debian support on the Pi.