Using Pico Plus 2 W more specifically. There are several sets of pins that can be used to connect to one of the two SPI peripherals. Can I connect multiple devices to SPI0 from both pins 2-3-4-5 and 18-19-20-21, or do I need all devices I want to connect to SPI0 to use the same set of pins?
The second one is true (from the RP2040 datasheet, section 2.19.2):
Each GPIO can have one function selected at a time. Likewise, each peripheral input (e.g. UART0 RX) should only be selected on one GPIO at a time. If the same peripheral input is connected to multiple GPIOs, the peripheral sees the logical OR of these GPIO inputs.