For using a wired microcontroller there are, if you are okay with using your network, ethernet boards like the Olimex POE board or the WT32-eth01 board that can be used with ESPHome.
Another option is to use a USB connected arduino board to the server, something I used in the past. You can use the serial integration for this to read out the output value of a sketch. Don’t have experience with sending data via USB to an arduino though. Did see this topic.
Edit: Firmata seems to be a good option as well, as it works over serial and works with YAML code.
And modbus can be an option as a wired protocol, using a USB to serial adapter.