For years, there has been a clear distinction between the Arduino and Raspberry Pi boards. There are some ... unlike the Nano (you can refer to the Pico pinout guide to avoid confusion).

The build improves on prior work by [rgco] with the Arduino Uno, with which they built a device ... taking 42 instruction cycles. Thanks to the Pi Pico’s faster clock speed and certain ...

We thought that connecting an Arduino to a Raspberry Pi was overkill, but one thing caught our attention. [Jan Stevens] mentions that the RPi is less expensive than the Ethernet Shield.