However, Arduino also offers this board without headers ... Additionally, the Nano and Micro feature 20 digital pins, labeled as RX, TX, D2 to D13, and A0 to A5. Among these, six (A0 to A5 ...

Of course, in addition to the five control lines, you need some handshaking lines, too so you could use as many as eight digital pins to control the device. The device in question is an ADG732.

Another noteworthy feature is the RX-TX switch function. Traditional Arduino boards assign digital pins in a specific order, but the UART interface on the RP2350 has a different configuration.